Drug Therapy

Study Overview

Objective. To assess the relative merits of ticagrelor compared to prasugrel in patients with acute coronary syndromes who will undergo invasive evaluation.

Design. Multicenter, open-label, prospective randomized controlled trial.

Setting and participants. A total of 4018 patients who presented with ACS with or without ST-segment elevation.

Intervention. Patients were randomly assigned to receive either ticagrelor or prasugrel.

Main outcome measures. The primary end point was the composite of death, myocardial infarction, or stroke at 1 year. The secondary end point was bleeding.

Main results. At 1 year, a primary end point event occurred in 184 of 2012 patients (9.3%) in the ticagrelor group and 137 of 2006 patients (6.9%) in the prasugrel group (hazard ratio [HR], 1.36; 95% confidence interval [CI], 1.09-1.70; P = 0.006). In the comparison between ticagrelor and prasugrel, the individual components of the primary end point were as follows: death, 4.5% versus 3.7%; myocardial infarction, 4.8% versus 3.0%; and stroke, 1.1% versus 1.0%, respectively. Definite or probable stent thrombosis occurred in 1.3% of patients assigned to ticagrelor and 1.0% in patients assigned to prasugrel. Major bleeding was observed in 5.4% of the patients in the ticagrelor group and 4.8% in the prasugrel group (HR, 1.12; 95% CI, 0.83-1.51, P = 0.46).

Conclusion. In patients who presented with ACS with or without ST-segment elevation, the incidence of death, myocardial infarction, or stroke was significantly lower among those who received prasugrel as compared to those who received ticagrelor, and incidence of major bleeding was not significantly different.

Dual antiplatelet therapy combining an adenosine disphosphate (ADP) receptor antagonist and aspirin is standard treatment for patients presenting with ACS. The limitation of clopidogrel has been its modest antiplatelet effect, with substantial interpatient variability. The newer generation thienopyridine prasugrel and the reversible direct-acting oral antagonist of the ADP receptor ticagrelor provide consistent and greater antiplatelet effect compared to clopidogrel. It has been previously reported that these agents are superior in reducing ischemic events when compared to clopidogrel.^1,2 Therefore, current guidelines recommend ticagrelor and prasugrel in preference to clopidogrel.^3,4 However, there has been no large randomized controlled study comparing the effect of ticagrelor and prasugrel. In this context, Shupke et al investigated this clinical question by performing a well-designed multicenter randomized controlled trial in patients presenting with ACS. At 12-month follow-up, the composite of death, myocardial infarction, and stroke occurred more frequently in the ticagrelor group compared to the prasugrel group (9.3% versus 6.9%; HR, 1.36; 95% CI, 1.09-1.70; P < 0.01). The incidence of major bleeding was not significantly different between the 2 groups (5.4% versus 4.8%; P = 0.46).

The strengths of this current study include the randomized design and the large number of patients enrolled, with adequate power to evaluate for superiority. This was a multicenter trial in Europe with 23 participating centers (21 from Germany). Furthermore, the interventional technique used by the operators reflects more contemporary technique compared to the previous studies comparing each agent to clopidogrel,^1,2 with more frequent use of radial access (37%) and drug-eluting stents (90%) and reduced use of GPIIb/IIIa inhibitors (12%).

There are a few important points to consider due to the differences between the 2 agents compared in this study. First, the loading dose of ticagrelor and prasugrel was administered differently in patients presenting with ACS without ST elevation. Ticagrelor was administered as soon as possible prior to the coronary angiogram, but prasugrel was administered after the coronary anatomy was defined prior to the intervention, which is how this agent is administered in current clinical practice. Therefore, this trial was an open-label study that compared not only different medications, but different administration strategies. Second, ticagrelor and prasugrel have different side-effect profiles. The side effects unique to ticagrelor are dyspnea and bradycardia. On the other hand, a contraindication unique to prasugrel is patients with a history of transient ischemic attack or stroke due to increased risk of thrombotic and hemorrhagic stroke.¹ In addition, prasugrel has increased bleeding risk in patients older than 75 years of age and those with low body weight (< 60 kg). In this study, the overall medication discontinuation rate was higher in the ticagrelor group specifically due to dyspnea, and the reduced dose of 5 mg of prasugrel was used in patients older than 75 years or with low body weight.

Since the timing of administration of ticagrelor (preloading prior to coronary angiography is recommended) is similar to that of clopidogrel, and given the theoretical benefit of reversible inhibition of the ADP receptor, ticagrelor has been used more commonly in clinical practice than prasugrel, and it has been implemented in the ACS protocol in many hospitals. In light of the results from this first head-to-head comparison utilizing more contemporary interventional techniques, these protocols may need to be adjusted in favor of prasugrel for patients presenting with ACS. However, given the difference in timing of administration and the difference in side-effect profile, operators must also tailor these agents depending on the patient profile.

Applications for Clinical Practice

In patients presenting with ACS, prasugrel was superior to ticagrelor, with a lower composite of death, myocardial infarction, and stroke at 12 months. Prasugrel should be considered as a first-line treatment for ACS.

– Taishi Hirai, MD, and Arun Kumar, MD, University of Missouri, Columbia, MO

Study Overview

Objective. To assess the relative merits of ticagrelor compared to prasugrel in patients with acute coronary syndromes who will undergo invasive evaluation.

Design. Multicenter, open-label, prospective randomized controlled trial.

Setting and participants. A total of 4018 patients who presented with ACS with or without ST-segment elevation.

Intervention. Patients were randomly assigned to receive either ticagrelor or prasugrel.

Main outcome measures. The primary end point was the composite of death, myocardial infarction, or stroke at 1 year. The secondary end point was bleeding.

Main results. At 1 year, a primary end point event occurred in 184 of 2012 patients (9.3%) in the ticagrelor group and 137 of 2006 patients (6.9%) in the prasugrel group (hazard ratio [HR], 1.36; 95% confidence interval [CI], 1.09-1.70; P = 0.006). In the comparison between ticagrelor and prasugrel, the individual components of the primary end point were as follows: death, 4.5% versus 3.7%; myocardial infarction, 4.8% versus 3.0%; and stroke, 1.1% versus 1.0%, respectively. Definite or probable stent thrombosis occurred in 1.3% of patients assigned to ticagrelor and 1.0% in patients assigned to prasugrel. Major bleeding was observed in 5.4% of the patients in the ticagrelor group and 4.8% in the prasugrel group (HR, 1.12; 95% CI, 0.83-1.51, P = 0.46).

Conclusion. In patients who presented with ACS with or without ST-segment elevation, the incidence of death, myocardial infarction, or stroke was significantly lower among those who received prasugrel as compared to those who received ticagrelor, and incidence of major bleeding was not significantly different.

Dual antiplatelet therapy combining an adenosine disphosphate (ADP) receptor antagonist and aspirin is standard treatment for patients presenting with ACS. The limitation of clopidogrel has been its modest antiplatelet effect, with substantial interpatient variability. The newer generation thienopyridine prasugrel and the reversible direct-acting oral antagonist of the ADP receptor ticagrelor provide consistent and greater antiplatelet effect compared to clopidogrel. It has been previously reported that these agents are superior in reducing ischemic events when compared to clopidogrel.^1,2 Therefore, current guidelines recommend ticagrelor and prasugrel in preference to clopidogrel.^3,4 However, there has been no large randomized controlled study comparing the effect of ticagrelor and prasugrel. In this context, Shupke et al investigated this clinical question by performing a well-designed multicenter randomized controlled trial in patients presenting with ACS. At 12-month follow-up, the composite of death, myocardial infarction, and stroke occurred more frequently in the ticagrelor group compared to the prasugrel group (9.3% versus 6.9%; HR, 1.36; 95% CI, 1.09-1.70; P < 0.01). The incidence of major bleeding was not significantly different between the 2 groups (5.4% versus 4.8%; P = 0.46).

The strengths of this current study include the randomized design and the large number of patients enrolled, with adequate power to evaluate for superiority. This was a multicenter trial in Europe with 23 participating centers (21 from Germany). Furthermore, the interventional technique used by the operators reflects more contemporary technique compared to the previous studies comparing each agent to clopidogrel,^1,2 with more frequent use of radial access (37%) and drug-eluting stents (90%) and reduced use of GPIIb/IIIa inhibitors (12%).

There are a few important points to consider due to the differences between the 2 agents compared in this study. First, the loading dose of ticagrelor and prasugrel was administered differently in patients presenting with ACS without ST elevation. Ticagrelor was administered as soon as possible prior to the coronary angiogram, but prasugrel was administered after the coronary anatomy was defined prior to the intervention, which is how this agent is administered in current clinical practice. Therefore, this trial was an open-label study that compared not only different medications, but different administration strategies. Second, ticagrelor and prasugrel have different side-effect profiles. The side effects unique to ticagrelor are dyspnea and bradycardia. On the other hand, a contraindication unique to prasugrel is patients with a history of transient ischemic attack or stroke due to increased risk of thrombotic and hemorrhagic stroke.¹ In addition, prasugrel has increased bleeding risk in patients older than 75 years of age and those with low body weight (< 60 kg). In this study, the overall medication discontinuation rate was higher in the ticagrelor group specifically due to dyspnea, and the reduced dose of 5 mg of prasugrel was used in patients older than 75 years or with low body weight.

Since the timing of administration of ticagrelor (preloading prior to coronary angiography is recommended) is similar to that of clopidogrel, and given the theoretical benefit of reversible inhibition of the ADP receptor, ticagrelor has been used more commonly in clinical practice than prasugrel, and it has been implemented in the ACS protocol in many hospitals. In light of the results from this first head-to-head comparison utilizing more contemporary interventional techniques, these protocols may need to be adjusted in favor of prasugrel for patients presenting with ACS. However, given the difference in timing of administration and the difference in side-effect profile, operators must also tailor these agents depending on the patient profile.

Applications for Clinical Practice

In patients presenting with ACS, prasugrel was superior to ticagrelor, with a lower composite of death, myocardial infarction, and stroke at 12 months. Prasugrel should be considered as a first-line treatment for ACS.

– Taishi Hirai, MD, and Arun Kumar, MD, University of Missouri, Columbia, MO

Study Overview

Objective. To assess the relative merits of ticagrelor compared to prasugrel in patients with acute coronary syndromes who will undergo invasive evaluation.

Design. Multicenter, open-label, prospective randomized controlled trial.

Setting and participants. A total of 4018 patients who presented with ACS with or without ST-segment elevation.

Intervention. Patients were randomly assigned to receive either ticagrelor or prasugrel.

Main outcome measures. The primary end point was the composite of death, myocardial infarction, or stroke at 1 year. The secondary end point was bleeding.

Main results. At 1 year, a primary end point event occurred in 184 of 2012 patients (9.3%) in the ticagrelor group and 137 of 2006 patients (6.9%) in the prasugrel group (hazard ratio [HR], 1.36; 95% confidence interval [CI], 1.09-1.70; P = 0.006). In the comparison between ticagrelor and prasugrel, the individual components of the primary end point were as follows: death, 4.5% versus 3.7%; myocardial infarction, 4.8% versus 3.0%; and stroke, 1.1% versus 1.0%, respectively. Definite or probable stent thrombosis occurred in 1.3% of patients assigned to ticagrelor and 1.0% in patients assigned to prasugrel. Major bleeding was observed in 5.4% of the patients in the ticagrelor group and 4.8% in the prasugrel group (HR, 1.12; 95% CI, 0.83-1.51, P = 0.46).

Conclusion. In patients who presented with ACS with or without ST-segment elevation, the incidence of death, myocardial infarction, or stroke was significantly lower among those who received prasugrel as compared to those who received ticagrelor, and incidence of major bleeding was not significantly different.

Dual antiplatelet therapy combining an adenosine disphosphate (ADP) receptor antagonist and aspirin is standard treatment for patients presenting with ACS. The limitation of clopidogrel has been its modest antiplatelet effect, with substantial interpatient variability. The newer generation thienopyridine prasugrel and the reversible direct-acting oral antagonist of the ADP receptor ticagrelor provide consistent and greater antiplatelet effect compared to clopidogrel. It has been previously reported that these agents are superior in reducing ischemic events when compared to clopidogrel.^1,2 Therefore, current guidelines recommend ticagrelor and prasugrel in preference to clopidogrel.^3,4 However, there has been no large randomized controlled study comparing the effect of ticagrelor and prasugrel. In this context, Shupke et al investigated this clinical question by performing a well-designed multicenter randomized controlled trial in patients presenting with ACS. At 12-month follow-up, the composite of death, myocardial infarction, and stroke occurred more frequently in the ticagrelor group compared to the prasugrel group (9.3% versus 6.9%; HR, 1.36; 95% CI, 1.09-1.70; P < 0.01). The incidence of major bleeding was not significantly different between the 2 groups (5.4% versus 4.8%; P = 0.46).

The strengths of this current study include the randomized design and the large number of patients enrolled, with adequate power to evaluate for superiority. This was a multicenter trial in Europe with 23 participating centers (21 from Germany). Furthermore, the interventional technique used by the operators reflects more contemporary technique compared to the previous studies comparing each agent to clopidogrel,^1,2 with more frequent use of radial access (37%) and drug-eluting stents (90%) and reduced use of GPIIb/IIIa inhibitors (12%).

There are a few important points to consider due to the differences between the 2 agents compared in this study. First, the loading dose of ticagrelor and prasugrel was administered differently in patients presenting with ACS without ST elevation. Ticagrelor was administered as soon as possible prior to the coronary angiogram, but prasugrel was administered after the coronary anatomy was defined prior to the intervention, which is how this agent is administered in current clinical practice. Therefore, this trial was an open-label study that compared not only different medications, but different administration strategies. Second, ticagrelor and prasugrel have different side-effect profiles. The side effects unique to ticagrelor are dyspnea and bradycardia. On the other hand, a contraindication unique to prasugrel is patients with a history of transient ischemic attack or stroke due to increased risk of thrombotic and hemorrhagic stroke.¹ In addition, prasugrel has increased bleeding risk in patients older than 75 years of age and those with low body weight (< 60 kg). In this study, the overall medication discontinuation rate was higher in the ticagrelor group specifically due to dyspnea, and the reduced dose of 5 mg of prasugrel was used in patients older than 75 years or with low body weight.

Since the timing of administration of ticagrelor (preloading prior to coronary angiography is recommended) is similar to that of clopidogrel, and given the theoretical benefit of reversible inhibition of the ADP receptor, ticagrelor has been used more commonly in clinical practice than prasugrel, and it has been implemented in the ACS protocol in many hospitals. In light of the results from this first head-to-head comparison utilizing more contemporary interventional techniques, these protocols may need to be adjusted in favor of prasugrel for patients presenting with ACS. However, given the difference in timing of administration and the difference in side-effect profile, operators must also tailor these agents depending on the patient profile.

Applications for Clinical Practice

In patients presenting with ACS, prasugrel was superior to ticagrelor, with a lower composite of death, myocardial infarction, and stroke at 12 months. Prasugrel should be considered as a first-line treatment for ACS.

– Taishi Hirai, MD, and Arun Kumar, MD, University of Missouri, Columbia, MO

Study Overview

Objective. To evaluate whether the combination of encorafenib plus cetuximab with or without the MEK inhibitor binimetinib would lead to longer overall survival (OS) than standard therapy in patients with metastatic BRAF V600E–mutated colorectal cancer.

Design. Global, multicenter, randomized, open-label, phase 3 trial.

Intervention. Patients were randomized in a 1:1:1 fashion to 1 of 3 groups: triplet-therapy group (encorafenib 300 mg daily, binimetinib 45 mg twice daily, and cetuximab 400 mg/m² of body surface area initially, then 250 mg/m² weekly), doublet-therapy group (encorafenib and cetuximab in same doses and schedule as the triplet-therapy group), and control group (investigators choice of cetuximab and irinotecan or cetuximab and FOLFIRI). The randomization was stratified by performance status and prior irinotecan use. Treatment was given until progression or unacceptable toxicities on a 28-day cycle. No crossover was permitted.

Setting and participants. 665 patients underwent randomization: 224 patients to triplet-therapy, 220 to doublet-therapy, and 221 to the control group. Eligible patients had histologically confirmed metastatic colorectal cancer with a BRAF V600E mutation. Patients all had disease progression after 1 or 2 previous lines of therapy.

Main outcome measures. The primary end point of the study was OS and objective response rate (ORR) in the triplet-therapy group compared with the control group. Secondary endpoints included OS in the doublet-therapy group compared with the control group, as well as progression-free survival (PFS), duration of response (DOR), and safety. Assessments were performed every 6 weeks for the first 24 weeks and then every 12 weeks thereafter.

Results. The baseline characteristics were well balanced between the treatment arms. At the time of data cutoff, the median duration of follow-up was 7.8 months for each group. The median OS was 9 months in the triplet-therapy group and 5.4 months in the control group (hazard ratio [HR] for death, 0.52; 95% confidence interval [CI], 0.39-0.70; P < 0.001). The median OS was 8.4 months for the doublet-therapy group, resulting in a significant reduction in the risk of death compared with the control group (HR, 0.6; 95% CI, 0.45-0.79; P < 0.001). The estimated 6-month survival was 71% for the triplet-therapy group, 65% for the doublet-therapy group, and 47% for the control group. The triplet-therapy group had a higher ORR compared with the control group (26% versus 2%, P < 0.001). The ORR in the doublet-therapy group was also significantly higher than that in the control group (20% versus 2%, P < 0.001). Complete responses were seen in 4% of patients in the triplet-therapy group, 5% of the doublet-therapy group, and no patients in the control group. PFS was significantly longer in both the triplet-therapy and doublet-therapy groups compared with the control group (median PFS: 4.3 months, 4.2 months, 1.5 months, respectively). This translated into a 62% and 60% reduction in the risk for disease progression or death in the triplet-therapy and doublet-therapy groups, respectively, compared to the control group.

The most common adverse event reported in the triplet-therapy group was gastrointestinal (GI) related (diarrhea, nausea, and vomiting), with grade 3 or higher GI toxicity seen in 10% of patients. Skin toxicity in the form of acneiform dermatitis was seen in almost 50% of those in the triplet-therapy arm; however, grade 3 or higher skin toxicity was uncommon (2%). Overall, adverse events grade 3 or higher were observed in 58% of those in the triplet-therapy group, 50% in the doublet-therapy group, and 61% in the control group. Adverse events leading to drug discontinuation occurred in 7% in the triplet-therapy group, 8% in the doublet-therapy group, and 11% in the control group. Three deaths were considered treatment related: 1 in the triplet-therapy group (bowel perforation) and 2 in the control group (anaphylaxis and respiratory failure).

Conclusion. The triplet-combination of encorafenib, binimetinib, and cetuximab as well as the doublet-regimen of encorafenib and cetuximab improved both PFS and OS in patients with metastatic, BRAF V600E–mutated colorectal cancer that has progressed after 1 or 2 lines of therapy.

Commentary

The current interim analysis of the BEACON CRC trial demonstrates improved response rates, PFS, and, importantly, OS with the triplet regimen of encorafenib, binimetinib, and cetuximab in patients with metastatic BRAF V600E–mutated colorectal cancer compared to standard irinotecan-based therapy. Similarly, a doublet-regimen of encorafenib and cetuximab also improved outcomes compared with irinotecan-based chemotherapy, resulting in significantly higher response rates, PFS, and OS.

BRAF mutations are seen in approximately 5% to 15% of colorectal cancers and are more commonly seen in right-sided disease. BRAF-mutated colorectal cancer has a poor prognosis, and the presence of a BRAF mutation is an independent prognostic factor for decreased survival.¹ Previous work to improve outcomes in this subset of patients has been largely disappointing. For example, Kopetz and colleagues have previously shown that single-agent BRAF inhibition with vemurafenib in metastatic BRAF-mutated colorectal cancer did not show meaningful clinical activity.² Preclinical studies have suggested that single-agent BRAF or MEK inhibition alone do not lead to sustained MAPK pathway inhibition. Mechanistically, inhibition of BRAF has been shown to lead to feedback activation of EGFR; thus, inhibition of BRAF alone does not lead to cessation of proliferation.³ In light of this, the combination of EGFR and BRAF inhibition has been an attractive therapeutic strategy. Yaeger and colleagues enrolled 15 patients in a pilot study looking at the efficacy and safety of the BRAF inhibitor vemurafenib and the EGFR antibody panitumumab in patients with BRAF-mutated metastatic colorectal cancer. In this cohort, combined BRAF and EGFR inhibition showed tumor regression in 10 of 12 patients.⁴ This finding was validated in other subsequent studies.⁵

The current study is the first phase 3 trial to validate the efficacy of BRAF, MEK, and EGFR inhibition in patients with BRAF-mutant metastatic colorectal cancer. The results of this study represent a very important step forward in treating this patient cohort that has historically had very poor clinical outcomes. The combination of encorafenib, binimetinib, and cetuximab improved OS by 48% compared with standard irinotecan-based chemotherapy. In light of this, we now have a chemotherapy-free targeted combination that improves survival and likely represents the new standard of care in patients with BRAF-mutated colorectal cancer after progression on 1 or 2 prior lines of therapy. Ongoing trials are being pursued to investigate the efficacy of these combinations in the upfront setting, and the results of these trials are eagerly awaited.

Applications for Clinical Practice

The combination of encorafenib, binimetinib, and cetuximab improved OS in patients with BRAF-mutated metastatic colorectal cancer after progression on 1 or 2 prior lines of therapy. This combination represents a potential new standard of care in this patient population.

–Daniel Isaac, DO, MS

Study Overview

Objective. To evaluate whether the combination of encorafenib plus cetuximab with or without the MEK inhibitor binimetinib would lead to longer overall survival (OS) than standard therapy in patients with metastatic BRAF V600E–mutated colorectal cancer.

Design. Global, multicenter, randomized, open-label, phase 3 trial.

Intervention. Patients were randomized in a 1:1:1 fashion to 1 of 3 groups: triplet-therapy group (encorafenib 300 mg daily, binimetinib 45 mg twice daily, and cetuximab 400 mg/m² of body surface area initially, then 250 mg/m² weekly), doublet-therapy group (encorafenib and cetuximab in same doses and schedule as the triplet-therapy group), and control group (investigators choice of cetuximab and irinotecan or cetuximab and FOLFIRI). The randomization was stratified by performance status and prior irinotecan use. Treatment was given until progression or unacceptable toxicities on a 28-day cycle. No crossover was permitted.

Setting and participants. 665 patients underwent randomization: 224 patients to triplet-therapy, 220 to doublet-therapy, and 221 to the control group. Eligible patients had histologically confirmed metastatic colorectal cancer with a BRAF V600E mutation. Patients all had disease progression after 1 or 2 previous lines of therapy.

Main outcome measures. The primary end point of the study was OS and objective response rate (ORR) in the triplet-therapy group compared with the control group. Secondary endpoints included OS in the doublet-therapy group compared with the control group, as well as progression-free survival (PFS), duration of response (DOR), and safety. Assessments were performed every 6 weeks for the first 24 weeks and then every 12 weeks thereafter.

Results. The baseline characteristics were well balanced between the treatment arms. At the time of data cutoff, the median duration of follow-up was 7.8 months for each group. The median OS was 9 months in the triplet-therapy group and 5.4 months in the control group (hazard ratio [HR] for death, 0.52; 95% confidence interval [CI], 0.39-0.70; P < 0.001). The median OS was 8.4 months for the doublet-therapy group, resulting in a significant reduction in the risk of death compared with the control group (HR, 0.6; 95% CI, 0.45-0.79; P < 0.001). The estimated 6-month survival was 71% for the triplet-therapy group, 65% for the doublet-therapy group, and 47% for the control group. The triplet-therapy group had a higher ORR compared with the control group (26% versus 2%, P < 0.001). The ORR in the doublet-therapy group was also significantly higher than that in the control group (20% versus 2%, P < 0.001). Complete responses were seen in 4% of patients in the triplet-therapy group, 5% of the doublet-therapy group, and no patients in the control group. PFS was significantly longer in both the triplet-therapy and doublet-therapy groups compared with the control group (median PFS: 4.3 months, 4.2 months, 1.5 months, respectively). This translated into a 62% and 60% reduction in the risk for disease progression or death in the triplet-therapy and doublet-therapy groups, respectively, compared to the control group.

The most common adverse event reported in the triplet-therapy group was gastrointestinal (GI) related (diarrhea, nausea, and vomiting), with grade 3 or higher GI toxicity seen in 10% of patients. Skin toxicity in the form of acneiform dermatitis was seen in almost 50% of those in the triplet-therapy arm; however, grade 3 or higher skin toxicity was uncommon (2%). Overall, adverse events grade 3 or higher were observed in 58% of those in the triplet-therapy group, 50% in the doublet-therapy group, and 61% in the control group. Adverse events leading to drug discontinuation occurred in 7% in the triplet-therapy group, 8% in the doublet-therapy group, and 11% in the control group. Three deaths were considered treatment related: 1 in the triplet-therapy group (bowel perforation) and 2 in the control group (anaphylaxis and respiratory failure).

Conclusion. The triplet-combination of encorafenib, binimetinib, and cetuximab as well as the doublet-regimen of encorafenib and cetuximab improved both PFS and OS in patients with metastatic, BRAF V600E–mutated colorectal cancer that has progressed after 1 or 2 lines of therapy.

Commentary

The current interim analysis of the BEACON CRC trial demonstrates improved response rates, PFS, and, importantly, OS with the triplet regimen of encorafenib, binimetinib, and cetuximab in patients with metastatic BRAF V600E–mutated colorectal cancer compared to standard irinotecan-based therapy. Similarly, a doublet-regimen of encorafenib and cetuximab also improved outcomes compared with irinotecan-based chemotherapy, resulting in significantly higher response rates, PFS, and OS.

BRAF mutations are seen in approximately 5% to 15% of colorectal cancers and are more commonly seen in right-sided disease. BRAF-mutated colorectal cancer has a poor prognosis, and the presence of a BRAF mutation is an independent prognostic factor for decreased survival.¹ Previous work to improve outcomes in this subset of patients has been largely disappointing. For example, Kopetz and colleagues have previously shown that single-agent BRAF inhibition with vemurafenib in metastatic BRAF-mutated colorectal cancer did not show meaningful clinical activity.² Preclinical studies have suggested that single-agent BRAF or MEK inhibition alone do not lead to sustained MAPK pathway inhibition. Mechanistically, inhibition of BRAF has been shown to lead to feedback activation of EGFR; thus, inhibition of BRAF alone does not lead to cessation of proliferation.³ In light of this, the combination of EGFR and BRAF inhibition has been an attractive therapeutic strategy. Yaeger and colleagues enrolled 15 patients in a pilot study looking at the efficacy and safety of the BRAF inhibitor vemurafenib and the EGFR antibody panitumumab in patients with BRAF-mutated metastatic colorectal cancer. In this cohort, combined BRAF and EGFR inhibition showed tumor regression in 10 of 12 patients.⁴ This finding was validated in other subsequent studies.⁵

The current study is the first phase 3 trial to validate the efficacy of BRAF, MEK, and EGFR inhibition in patients with BRAF-mutant metastatic colorectal cancer. The results of this study represent a very important step forward in treating this patient cohort that has historically had very poor clinical outcomes. The combination of encorafenib, binimetinib, and cetuximab improved OS by 48% compared with standard irinotecan-based chemotherapy. In light of this, we now have a chemotherapy-free targeted combination that improves survival and likely represents the new standard of care in patients with BRAF-mutated colorectal cancer after progression on 1 or 2 prior lines of therapy. Ongoing trials are being pursued to investigate the efficacy of these combinations in the upfront setting, and the results of these trials are eagerly awaited.

Applications for Clinical Practice

The combination of encorafenib, binimetinib, and cetuximab improved OS in patients with BRAF-mutated metastatic colorectal cancer after progression on 1 or 2 prior lines of therapy. This combination represents a potential new standard of care in this patient population.

–Daniel Isaac, DO, MS

Study Overview

Objective. To evaluate whether the combination of encorafenib plus cetuximab with or without the MEK inhibitor binimetinib would lead to longer overall survival (OS) than standard therapy in patients with metastatic BRAF V600E–mutated colorectal cancer.

Design. Global, multicenter, randomized, open-label, phase 3 trial.

Intervention. Patients were randomized in a 1:1:1 fashion to 1 of 3 groups: triplet-therapy group (encorafenib 300 mg daily, binimetinib 45 mg twice daily, and cetuximab 400 mg/m² of body surface area initially, then 250 mg/m² weekly), doublet-therapy group (encorafenib and cetuximab in same doses and schedule as the triplet-therapy group), and control group (investigators choice of cetuximab and irinotecan or cetuximab and FOLFIRI). The randomization was stratified by performance status and prior irinotecan use. Treatment was given until progression or unacceptable toxicities on a 28-day cycle. No crossover was permitted.

Setting and participants. 665 patients underwent randomization: 224 patients to triplet-therapy, 220 to doublet-therapy, and 221 to the control group. Eligible patients had histologically confirmed metastatic colorectal cancer with a BRAF V600E mutation. Patients all had disease progression after 1 or 2 previous lines of therapy.

Main outcome measures. The primary end point of the study was OS and objective response rate (ORR) in the triplet-therapy group compared with the control group. Secondary endpoints included OS in the doublet-therapy group compared with the control group, as well as progression-free survival (PFS), duration of response (DOR), and safety. Assessments were performed every 6 weeks for the first 24 weeks and then every 12 weeks thereafter.

Results. The baseline characteristics were well balanced between the treatment arms. At the time of data cutoff, the median duration of follow-up was 7.8 months for each group. The median OS was 9 months in the triplet-therapy group and 5.4 months in the control group (hazard ratio [HR] for death, 0.52; 95% confidence interval [CI], 0.39-0.70; P < 0.001). The median OS was 8.4 months for the doublet-therapy group, resulting in a significant reduction in the risk of death compared with the control group (HR, 0.6; 95% CI, 0.45-0.79; P < 0.001). The estimated 6-month survival was 71% for the triplet-therapy group, 65% for the doublet-therapy group, and 47% for the control group. The triplet-therapy group had a higher ORR compared with the control group (26% versus 2%, P < 0.001). The ORR in the doublet-therapy group was also significantly higher than that in the control group (20% versus 2%, P < 0.001). Complete responses were seen in 4% of patients in the triplet-therapy group, 5% of the doublet-therapy group, and no patients in the control group. PFS was significantly longer in both the triplet-therapy and doublet-therapy groups compared with the control group (median PFS: 4.3 months, 4.2 months, 1.5 months, respectively). This translated into a 62% and 60% reduction in the risk for disease progression or death in the triplet-therapy and doublet-therapy groups, respectively, compared to the control group.

The most common adverse event reported in the triplet-therapy group was gastrointestinal (GI) related (diarrhea, nausea, and vomiting), with grade 3 or higher GI toxicity seen in 10% of patients. Skin toxicity in the form of acneiform dermatitis was seen in almost 50% of those in the triplet-therapy arm; however, grade 3 or higher skin toxicity was uncommon (2%). Overall, adverse events grade 3 or higher were observed in 58% of those in the triplet-therapy group, 50% in the doublet-therapy group, and 61% in the control group. Adverse events leading to drug discontinuation occurred in 7% in the triplet-therapy group, 8% in the doublet-therapy group, and 11% in the control group. Three deaths were considered treatment related: 1 in the triplet-therapy group (bowel perforation) and 2 in the control group (anaphylaxis and respiratory failure).

Conclusion. The triplet-combination of encorafenib, binimetinib, and cetuximab as well as the doublet-regimen of encorafenib and cetuximab improved both PFS and OS in patients with metastatic, BRAF V600E–mutated colorectal cancer that has progressed after 1 or 2 lines of therapy.

Commentary

The current interim analysis of the BEACON CRC trial demonstrates improved response rates, PFS, and, importantly, OS with the triplet regimen of encorafenib, binimetinib, and cetuximab in patients with metastatic BRAF V600E–mutated colorectal cancer compared to standard irinotecan-based therapy. Similarly, a doublet-regimen of encorafenib and cetuximab also improved outcomes compared with irinotecan-based chemotherapy, resulting in significantly higher response rates, PFS, and OS.

BRAF mutations are seen in approximately 5% to 15% of colorectal cancers and are more commonly seen in right-sided disease. BRAF-mutated colorectal cancer has a poor prognosis, and the presence of a BRAF mutation is an independent prognostic factor for decreased survival.¹ Previous work to improve outcomes in this subset of patients has been largely disappointing. For example, Kopetz and colleagues have previously shown that single-agent BRAF inhibition with vemurafenib in metastatic BRAF-mutated colorectal cancer did not show meaningful clinical activity.² Preclinical studies have suggested that single-agent BRAF or MEK inhibition alone do not lead to sustained MAPK pathway inhibition. Mechanistically, inhibition of BRAF has been shown to lead to feedback activation of EGFR; thus, inhibition of BRAF alone does not lead to cessation of proliferation.³ In light of this, the combination of EGFR and BRAF inhibition has been an attractive therapeutic strategy. Yaeger and colleagues enrolled 15 patients in a pilot study looking at the efficacy and safety of the BRAF inhibitor vemurafenib and the EGFR antibody panitumumab in patients with BRAF-mutated metastatic colorectal cancer. In this cohort, combined BRAF and EGFR inhibition showed tumor regression in 10 of 12 patients.⁴ This finding was validated in other subsequent studies.⁵

The current study is the first phase 3 trial to validate the efficacy of BRAF, MEK, and EGFR inhibition in patients with BRAF-mutant metastatic colorectal cancer. The results of this study represent a very important step forward in treating this patient cohort that has historically had very poor clinical outcomes. The combination of encorafenib, binimetinib, and cetuximab improved OS by 48% compared with standard irinotecan-based chemotherapy. In light of this, we now have a chemotherapy-free targeted combination that improves survival and likely represents the new standard of care in patients with BRAF-mutated colorectal cancer after progression on 1 or 2 prior lines of therapy. Ongoing trials are being pursued to investigate the efficacy of these combinations in the upfront setting, and the results of these trials are eagerly awaited.

Applications for Clinical Practice

The combination of encorafenib, binimetinib, and cetuximab improved OS in patients with BRAF-mutated metastatic colorectal cancer after progression on 1 or 2 prior lines of therapy. This combination represents a potential new standard of care in this patient population.

–Daniel Isaac, DO, MS

Certain types of oral antibiotics seem to be associated with an elevated risk of Parkinson’s disease with a delay that is consistent with the proposed duration of a prodromal period, according to a report published in Movement Disorders. Associations were found for broad-spectrum antibiotics and those that act against anaerobic bacteria and fungi. The timing of antibiotic exposure also seemed to matter.

In a nationwide case-control study, Finnish researchers compared data on antibiotic use in 13,976 individuals diagnosed with Parkinson’s disease between 1998 and 2014 with antibiotic-use data from 40,697 controls. The strongest connection with Parkinson’s disease risk was found for oral exposure to macrolides and lincosamides (adjusted odds ratio up to 1.416). After correction for multiple comparisons, exposure to antianaerobics and tetracyclines 10-15 years before the index date, and antifungal medications 1-5 years before the index date were positively associated with Parkinson’s disease risk. In post hoc analyses, further positive associations were found for broad-spectrum antibiotics.

Tuomas H. Mertsalmi, MD, from the Helsinki University Hospital and coauthors reported that this was the first study to explore a possible connection between antimicrobial use and Parkinson’s disease.

“In Parkinson’s disease, several studies have described alterations of gut microbiota composition, and changes in fecal microbiota abundance have been found to be associated with gastrointestinal and motor symptoms,” they wrote.

Commenting on the delay between the exposure and diagnosis for the most strongly associated antimicrobials, the authors noted that this 10-15 year lag was comparable with what has been found between the peripheral initiation of Parkinson’s disease and its motor manifestation.

“This would also explain the lack of association between antibiotic exposure 1-5 years before index date – if antibiotic exposure could induce or contribute to the pathogenesis of Parkinson’s disease in the gastrointestinal tract, it would probably take several years before the clinical manifestation of Parkinson’s disease,” they wrote.

With regards to the association seen for sulfonamides and trimethoprim – which was 1-5 years before the index date – they speculated this could reflect treatment for urinary tract infections, which individuals with Parkinson’s disease might be more susceptible to in the prodromal phase of the disease.

The authors noted that infectious disease has also been associated with Parkinson’s disease, and that their analysis did not include information about why the antimicrobial agents were prescribed. However, they pointed out that the associations were only for certain antibiotic classes, which makes it unlikely that the association was related to greater burden of infectious disease among individuals with Parkinson’s disease.

The pattern of associations supports the hypothesis that effects on gut microbiota could link antibiotics to Parkinson’s disease. “The link between antibiotic exposure and Parkinson’s disease fits the current view that in a significant proportion of patients the pathology of Parkinson’s disease may originate in the gut, possibly related to microbial changes, years before the onset of typical Parkinson’s disease motor symptoms such as slowness, muscle stiffness, and shaking of the extremities. It was known that bacterial composition of the intestine in patients with Parkinson’s disease is abnormal, but the cause is unclear. Our results suggest that some commonly used antibiotics, which are known to strongly influence the gut microbiota, could be a predisposing factor,” said lead investigator Filip Scheperjans, MD, PhD, from the department of neurology at Helsinki University Hospital.

The findings may have implications for antibiotic prescribing practices in the future, said Dr. Scheperjans. “In addition to the problem of antibiotic resistance, antimicrobial prescribing should also take into account their potentially long-lasting effects on the gut microbiome and the development of certain diseases.”

The study was funded by the Finnish Parkinson Foundation, the Finnish Medical Foundation, the Maire Taponen Foundation, and the Academy of Finland. One author declared relevant patents and his position as founder and chief executive of a private company. No other conflicts of interest were declared.

SOURCE: Mertsalmi TH et al. Mov Disord. 2019 Nov 18. doi: 10.1002/mds.27924.

Certain types of oral antibiotics seem to be associated with an elevated risk of Parkinson’s disease with a delay that is consistent with the proposed duration of a prodromal period, according to a report published in Movement Disorders. Associations were found for broad-spectrum antibiotics and those that act against anaerobic bacteria and fungi. The timing of antibiotic exposure also seemed to matter.

In a nationwide case-control study, Finnish researchers compared data on antibiotic use in 13,976 individuals diagnosed with Parkinson’s disease between 1998 and 2014 with antibiotic-use data from 40,697 controls. The strongest connection with Parkinson’s disease risk was found for oral exposure to macrolides and lincosamides (adjusted odds ratio up to 1.416). After correction for multiple comparisons, exposure to antianaerobics and tetracyclines 10-15 years before the index date, and antifungal medications 1-5 years before the index date were positively associated with Parkinson’s disease risk. In post hoc analyses, further positive associations were found for broad-spectrum antibiotics.

Tuomas H. Mertsalmi, MD, from the Helsinki University Hospital and coauthors reported that this was the first study to explore a possible connection between antimicrobial use and Parkinson’s disease.

“In Parkinson’s disease, several studies have described alterations of gut microbiota composition, and changes in fecal microbiota abundance have been found to be associated with gastrointestinal and motor symptoms,” they wrote.

Commenting on the delay between the exposure and diagnosis for the most strongly associated antimicrobials, the authors noted that this 10-15 year lag was comparable with what has been found between the peripheral initiation of Parkinson’s disease and its motor manifestation.

“This would also explain the lack of association between antibiotic exposure 1-5 years before index date – if antibiotic exposure could induce or contribute to the pathogenesis of Parkinson’s disease in the gastrointestinal tract, it would probably take several years before the clinical manifestation of Parkinson’s disease,” they wrote.

With regards to the association seen for sulfonamides and trimethoprim – which was 1-5 years before the index date – they speculated this could reflect treatment for urinary tract infections, which individuals with Parkinson’s disease might be more susceptible to in the prodromal phase of the disease.

The authors noted that infectious disease has also been associated with Parkinson’s disease, and that their analysis did not include information about why the antimicrobial agents were prescribed. However, they pointed out that the associations were only for certain antibiotic classes, which makes it unlikely that the association was related to greater burden of infectious disease among individuals with Parkinson’s disease.

The pattern of associations supports the hypothesis that effects on gut microbiota could link antibiotics to Parkinson’s disease. “The link between antibiotic exposure and Parkinson’s disease fits the current view that in a significant proportion of patients the pathology of Parkinson’s disease may originate in the gut, possibly related to microbial changes, years before the onset of typical Parkinson’s disease motor symptoms such as slowness, muscle stiffness, and shaking of the extremities. It was known that bacterial composition of the intestine in patients with Parkinson’s disease is abnormal, but the cause is unclear. Our results suggest that some commonly used antibiotics, which are known to strongly influence the gut microbiota, could be a predisposing factor,” said lead investigator Filip Scheperjans, MD, PhD, from the department of neurology at Helsinki University Hospital.

The findings may have implications for antibiotic prescribing practices in the future, said Dr. Scheperjans. “In addition to the problem of antibiotic resistance, antimicrobial prescribing should also take into account their potentially long-lasting effects on the gut microbiome and the development of certain diseases.”

The study was funded by the Finnish Parkinson Foundation, the Finnish Medical Foundation, the Maire Taponen Foundation, and the Academy of Finland. One author declared relevant patents and his position as founder and chief executive of a private company. No other conflicts of interest were declared.

SOURCE: Mertsalmi TH et al. Mov Disord. 2019 Nov 18. doi: 10.1002/mds.27924.

Certain types of oral antibiotics seem to be associated with an elevated risk of Parkinson’s disease with a delay that is consistent with the proposed duration of a prodromal period, according to a report published in Movement Disorders. Associations were found for broad-spectrum antibiotics and those that act against anaerobic bacteria and fungi. The timing of antibiotic exposure also seemed to matter.

In a nationwide case-control study, Finnish researchers compared data on antibiotic use in 13,976 individuals diagnosed with Parkinson’s disease between 1998 and 2014 with antibiotic-use data from 40,697 controls. The strongest connection with Parkinson’s disease risk was found for oral exposure to macrolides and lincosamides (adjusted odds ratio up to 1.416). After correction for multiple comparisons, exposure to antianaerobics and tetracyclines 10-15 years before the index date, and antifungal medications 1-5 years before the index date were positively associated with Parkinson’s disease risk. In post hoc analyses, further positive associations were found for broad-spectrum antibiotics.

Tuomas H. Mertsalmi, MD, from the Helsinki University Hospital and coauthors reported that this was the first study to explore a possible connection between antimicrobial use and Parkinson’s disease.

“In Parkinson’s disease, several studies have described alterations of gut microbiota composition, and changes in fecal microbiota abundance have been found to be associated with gastrointestinal and motor symptoms,” they wrote.

Commenting on the delay between the exposure and diagnosis for the most strongly associated antimicrobials, the authors noted that this 10-15 year lag was comparable with what has been found between the peripheral initiation of Parkinson’s disease and its motor manifestation.

“This would also explain the lack of association between antibiotic exposure 1-5 years before index date – if antibiotic exposure could induce or contribute to the pathogenesis of Parkinson’s disease in the gastrointestinal tract, it would probably take several years before the clinical manifestation of Parkinson’s disease,” they wrote.

With regards to the association seen for sulfonamides and trimethoprim – which was 1-5 years before the index date – they speculated this could reflect treatment for urinary tract infections, which individuals with Parkinson’s disease might be more susceptible to in the prodromal phase of the disease.

The authors noted that infectious disease has also been associated with Parkinson’s disease, and that their analysis did not include information about why the antimicrobial agents were prescribed. However, they pointed out that the associations were only for certain antibiotic classes, which makes it unlikely that the association was related to greater burden of infectious disease among individuals with Parkinson’s disease.

The pattern of associations supports the hypothesis that effects on gut microbiota could link antibiotics to Parkinson’s disease. “The link between antibiotic exposure and Parkinson’s disease fits the current view that in a significant proportion of patients the pathology of Parkinson’s disease may originate in the gut, possibly related to microbial changes, years before the onset of typical Parkinson’s disease motor symptoms such as slowness, muscle stiffness, and shaking of the extremities. It was known that bacterial composition of the intestine in patients with Parkinson’s disease is abnormal, but the cause is unclear. Our results suggest that some commonly used antibiotics, which are known to strongly influence the gut microbiota, could be a predisposing factor,” said lead investigator Filip Scheperjans, MD, PhD, from the department of neurology at Helsinki University Hospital.

The findings may have implications for antibiotic prescribing practices in the future, said Dr. Scheperjans. “In addition to the problem of antibiotic resistance, antimicrobial prescribing should also take into account their potentially long-lasting effects on the gut microbiome and the development of certain diseases.”

The study was funded by the Finnish Parkinson Foundation, the Finnish Medical Foundation, the Maire Taponen Foundation, and the Academy of Finland. One author declared relevant patents and his position as founder and chief executive of a private company. No other conflicts of interest were declared.

SOURCE: Mertsalmi TH et al. Mov Disord. 2019 Nov 18. doi: 10.1002/mds.27924.

Electronic cigarettes and other “vaping” devices have been increasing in popularity among youth and adults since their introduction in the US market in 2007.¹ This increase is partially driven by a public perception that vaping is harmless, or at least less harmful than cigarette smoking.² Vaping fans also argue that current smokers can use vaping as nicotine replacement therapy to help them quit smoking.³

We disagree. Research on the health effects of vaping, though still limited, is accumulating rapidly and making it increasingly clear that this habit is far from harmless. For youth, it is a gateway to addiction to nicotine and other substances. Whether it can help people quit smoking remains to be seen. And recent months have seen reports of serious respiratory illnesses and even deaths linked to vaping.⁴

In December 2016, the US Surgeon General warned that e-cigarette use among youth and young adults in the United States represents a “major public health concern,”⁵ and that more adolescents and young adults are now vaping than smoking conventional tobacco products.

This article reviews the issue of vaping in the United States, as well as available evidence regarding its safety.

YOUTH AT RISK

Retail sales of e-cigarettes and vaping devices approach an annual $7 billion.⁶ A 2014–2015 survey found that 2.4% of the general US population were current users of e-cigarettes, and 8.5% had tried them at least once.³

In 2014, for the first time, e-cigarette use became more common among US youth than traditional cigarettes.⁵

The odds of taking up vaping are higher among minority youth in the United States, particularly Hispanics.⁹ This trend is particularly worrisome because several longitudinal studies have shown that adolescents who use e-cigarettes are 3 times as likely to eventually become smokers of traditional cigarettes compared with adolescents who do not use e-cigarettes.^10–12

If US youth continue smoking at the current rate, 5.6 million of the current population under age 18, or 1 of every 13, will die early of a smoking-related illness.¹³ 

RECENT OUTBREAK OF VAPING-ASSOCIATED LUNG INJURY

As of November 5, 2019, there had been 2,051 cases of vaping-associated lung injury in 49 states (all except Alaska), the District of Columbia, and 1 US territory reported to the US Centers for Disease Control and Prevention (CDC), with 39 confirmed deaths.⁴ The reported cases include respiratory injury including acute eosinophilic pneumonia, organizing pneumonia, acute respiratory distress syndrome, and hypersensitivity pneumonitis.¹⁴

Most of these patients had been vaping tetrahydrocannabinol (THC), though many used both nicotine- and THC-containing products, and others used products containing nicotine exclusively.⁴ Thus, it is difficult to identify the exact substance or substances that may be contributing to this sudden outbreak among vape users, and many different product sources are currently under investigation.

One substance that may be linked to the epidemic is vitamin E acetate, which the New York State Department of Health has detected in high levels in cannabis vaping cartridges used by patients who developed lung injury.¹⁵ The US Food and Drug Administration (FDA) is continuing to analyze vape cartridge samples submitted by affected patients to look for other chemicals that can contribute to the development of serious pulmonary illness.

Source: The US Food and Drug Administration

Vape pens consist of similar elements but are not necessarily similar in appearance to a conventional cigarette, and may look more like a pen or a USB flash drive. In fact, the Juul device is recharged by plugging it into a USB port.

Vaping devices have many street names, including e-cigs, e-hookahs, vape pens, mods, vapes, and tank systems.

The first US patent application for a device resembling a modern e-cigarette was filed in 1963, but the product never made it to the market.¹⁶ Instead, the first commercially successful e-cigarette was created in Beijing in 2003 and introduced to US markets in 2007.

Newer-generation devices have larger batteries and can heat the liquid to higher temperatures, releasing more nicotine and forming additional toxicants such as formaldehyde. Devices lack standardization in terms of design, capacity for safely holding e-liquid, packaging of the e-liquid, and features designed to minimize hazards of use.

Not just nicotine

Many devices are designed for use with other drugs, including THC.¹⁷ In a 2018 study, 10.9% of college students reported vaping marijuana in the past 30 days, up from 5.2% in 2017.¹⁸

Other substances are being vaped as well.¹⁹ In theory, any heat-stable psychoactive recreational drug could be aerosolized and vaped. There are increasing reports of e-liquids containing recreational drugs such as synthetic cannabinoid receptor agonists, crack cocaine, LSD, and methamphetamine.¹⁷

Freedom, rebellion, glamour

Sales have risen rapidly since 2007 with widespread advertising on television and in print publications for popular brands, often featuring celebrities.²⁰ Spending on advertising for e-cigarettes and vape devices rose from $6.4 million in 2011 to $115 million in 2014—and that was before the advent of Juul (see below).²¹

Marketing campaigns for vaping devices mimic the themes previously used successfully by the tobacco industry, eg, freedom, rebellion, and glamour. They also make unsubstantiated claims about health benefits and smoking cessation, though initial websites contained endorsements from physicians, similar to the strategies of tobacco companies in old cigarette ads. Cigarette ads have been prohibited since 1971—but not e-cigarette ads. Moreover, vaping products appear as product placements in television shows and movies, with advocacy groups on social media.²²

By law, buyers have to be 18 or 21

Vaping devices can be purchased at vape shops, convenience stores, gas stations, and over the Internet; up to 50% of sales are conducted online.²⁴

Fruit flavors are popular

Zhu et al²⁵ estimated that 7,700 unique vaping flavors exist, with fruit and candy flavors predominating. The most popular flavors are tobacco and mint, followed by fruit, dessert and candy flavors, alcoholic flavors (strawberry daiquiri, margarita), and food flavors.²⁵ These flavors have been associated with higher usage in youth, leading to increased risk of nicotine addiction.²⁶

WHAT IS JUUL?

The Juul device (Juul Labs, www.juul.com) was developed in 2015 by 2 Stanford University graduates. Their goal was to produce a more satisfying and cigarette-like vaping experience, specifically by increasing the amount of nicotine delivered while maintaining smooth and pleasant inhalation. They created an e-liquid that could be vaporized effectively at lower temperatures.²⁷

While more than 400 brands of vaping devices are currently available in the United States,³ Juul has held the largest market share since 2017,²⁸ an estimated 72.1% as of August 2018.²⁹ The surge in popularity of this particular brand is attributed to its trendy design that is similar in size and appearance to a USB flash drive,²⁹ and its offering of sweet flavors such as “crème brûlée” and “cool mint.”

On April 24, 2018, in view of growing concern about the popularity of Juul products among youth, the FDA requested that the company submit documents regarding its marketing tactics, as well as research on the effects of this marketing on product design and public health impact, and information about adverse experiences and complaints.³⁰ The company was forced to change its marketing to appeal less to youth. Now it offers only 3 flavors: “Virginia tobacco,” “classic tobacco,” and “menthol,” although off-brand pods containing a variety of flavors are still available. And some pods are refillable, so users can essentially vape any substance they want.

Although the Juul device delivers a strong dose of nicotine, it is small and therefore easy to hide from parents and teachers, and widespread use has been reported among youth in middle and high schools. Hoodies, hemp jewelry, and backpacks have been designed to hide the devices and allow for easy, hands-free use. YouTube searches for terms such as “Juul,” “hiding Juul at school,” and “Juul in class,” yield thousands of results.³¹ A 2017 survey reported that 8% of Americans age 15 to 24 had used Juul in the month prior to the survey.³² “To juul” has become a verb.

Each Juul starter kit contains the rechargeable inhalation device plus 4 flavored pods. In the United States, each Juul pod contains nearly as much nicotine as 1 pack of 20 cigarettes in a concentration of 3% or 5%. (Israel and Europe have forced the company to replace the 5% nicotine pods with 1.7% nicotine pods.³³) A starter kit costs $49.99, and additional packs of 4 flavored liquid cartridges or pods cost $15.99.³⁴ Other brands of vape pens cost between $15 and $35, and 10-mL bottles of e-liquid cost approximately $⁷.

What is ‘dripping’?

Hard-core vapers seeking a more intense experience are taking their vaping devices apart and modifying them for “dripping,” ie, directly dripping vape liquids onto the heated coils for inhalation. In a survey, 1 in 4 high school students using vape devices also used them for dripping, citing desires for a thicker cloud of vapor, more intense flavor, “a stronger throat hit,” curiosity, and other reasons.³⁵ Dripping involves higher temperatures, which leads to higher amounts of nicotine delivered, along with more formaldehyde, acetaldehyde, and acetone (see below).³⁶

Studies of vape liquids consistently confirm the presence of toxic substances in the resulting vape aerosol.^37–40 Depending on the combination of flavorings and solvents in a given e-liquid, a variety of chemicals can be detected in the aerosol from various vaping devices. Chemicals that may be detected include known irritants of respiratory mucosa, as well as various carcinogens. The list includes:

• Organic volatile compounds such as propylene glycol, glycerin, and toluene
• Aldehydes such as formaldehyde (released when propylene glycol is heated to high temperatures), acetaldehyde, and benzaldehyde
• Acetone and acrolein
• Carcinogenic nitrosamines
• Polycyclic aromatic hydrocarbons
• Particulate matter
• Metals including chromium, cadmium, nickel, and lead; and particles of copper, nickel, and silver have been found in electronic nicotine delivery system aerosol in higher levels than in conventional cigarette smoke.⁴¹

The specific chemicals detected can vary greatly between brands, even when the flavoring and nicotine content are equivalent, which frequently results in inconsistent and conflicting study findings. The chemicals detected also vary with the voltage or power used to generate the aerosol. Different flavors may carry varying levels of risk; for example, mint- and menthol-flavored e-cigarettes were shown to expose users to dangerous levels of pulegone, a carcinogenic compound banned as a food additive in 2018.⁴² The concentrations of some of these chemicals are sufficiently high to be of toxicologic concern; for example, one study reported the presence of benzaldehyde in e-cigarette aerosol at twice the workplace exposure limit.⁴³

Biologic effects

In an in vitro study,⁴⁴ 57% of e-liquids studied were found to be cytotoxic to human pulmonary fibroblasts, lung epithelial cells, and human embryonic stem cells. Fruit-flavored e-liquids in particular caused a significant increase in DNA fragmentation. Cell cultures treated with e-cigarette liquids showed increased oxidative stress, reduced cell proliferation, and increased DNA damage,⁴⁴ which may have implications for carcinogenic risk.

In another study,⁴⁵ exposure to e-cigarette aerosol as well as conventional cigarette smoke resulted in suppression of genes related to immune and inflammatory response in respiratory epithelial cells. All genes with decreased expression after exposure to conventional cigarette smoke also showed decreased expression with exposure to e-cigarette smoke, which the study authors suggested could lead to immune suppression at the level of the nasal mucosa. Diacetyl and acetoin, chemicals found in certain flavorings, have been linked to bronchiolitis obliterans, or “popcorn lung.”⁴⁶

Nicotine is not benign

The nicotine itself in many vaping liquids should also not be underestimated. Nicotine has harmful neurocognitive effects and addictive properties, particularly in the developing brains of adolescents and young adults.⁴⁷ Nicotine exposure during adolescence negatively affects memory, attention, and emotional regulation,⁴⁸ as well as executive functioning, reward processing, and learning.⁴⁹

The brain undergoes major structural remodeling in adolescence, and nicotine acetylcholine receptors regulate neural maturation. Early exposure to nicotine disrupts this process, leading to poor executive functioning, difficulty learning, decreased memory, and issues with reward processing.

Fetal exposure, if nicotine products are used during pregnancy, has also been linked to adverse consequences such as deficits in attention and cognition, behavioral effects, and sudden infant death syndrome.⁵

Much to learn about toxicity

Partly because vaping devices have been available to US consumers only since 2007, limited evidence is available regarding the long-term effects of exposure to the aerosol from these devices in humans.¹ Many of the studies mentioned above were in vitro studies or conducted in mouse models. Differences in device design and the composition of the e-liquid among device brands pose a challenge for developing well-designed studies of the long-term health effects of e-cigarette and vape use. Additionally, devices may have different health impacts when used to vape cannabis or other drugs besides nicotine, which requires further investigation.

E-CIGARETTES AND SMOKING CESSATION

Conventional cigarette smoking is a major public health threat, as tobacco use is responsible for 480,000 deaths annually in the United States.⁵⁰

And smoking is extremely difficult to quit: as many as 80% of smokers who attempt to quit resume smoking within the first month.⁵¹ The chance of successfully quitting improves by over 50% if the individual undergoes nicotine replacement therapy, and it improves even more with counseling.⁵⁰

There are currently 5 types of FDA-approved nicotine replacement therapy products (gum, patch, lozenge, inhaler, nasal spray) to help with smoking cessation. In addition, 2 non-nicotine prescription drugs (varenicline and bupropion) have been approved for treating tobacco dependence.

Can vaping devices be added to the list of nicotine replacement therapy products? Although some manufacturers try to brand their devices as smoking cessation aids, in one study,⁵² one-third of e-cigarette users said they had either never used conventional cigarettes or had formerly smoked them.

Bullen et al⁵³ randomized smokers interested in quitting to receive either e-cigarettes, nicotine patches, or placebo (nicotine-free) e-cigarettes and followed them for 6 months. Rates of tobacco cessation were less than predicted for the entire study population, resulting in insufficient power to determine the superiority of any single method, but the study authors concluded that nicotine e-cigarettes were “modestly effective” at helping smokers quit, and that abstinence rates may be similar to those with nicotine patches.⁵³

Hajek et al⁵⁴ randomized 886 smokers to e-cigarette or nicotine replacement products of their choice. After 1 year, 18% of e-cigarette users had stopped smoking, compared with  9.9% of nicotine replacement product users. However, 80% of the e-cigarette users were still using e-cigarettes after 1 year, while only 9% of nicotine replacement product users were still using nicotine replacement therapy products after 1 year.

While quitting conventional cigarette smoking altogether has widely established health benefits, little is known about the health benefits of transitioning from conventional cigarette smoking to reduced conventional cigarette smoking with concomitant use of e-cigarettes.

Campagna et al⁵⁵ found no beneficial health effects in smokers who partially substituted conventional cigarettes for e-cigarettes.

Many studies found that smokers use e-cigarettes to maintain their habit instead of quitting entirely.⁵⁶ It has been suggested that any slight increase in effectiveness in smoking cessation by using e-cigarettes compared with other nicotine replacement products could be linked to satisfying of the habitual smoking actions, such as inhaling and bringing the hand to the mouth,²⁴ which are absent when using other nicotine replacement methods such as a nicotine patch.

As with safety information, long-term outcomes regarding the use of vape devices for smoking cessation have not been yet established, as this option is still relatively new.

Another worrisome trend involving electronic nicotine delivery systems is their marketing and branding, which appear to be aimed directly at adolescents and young adults. Juul and other similar products cannot be sold to anyone under the age of 18 (or 21 in 18 states, including California, Massachusetts, New York, and now Ohio). Despite this, Juul and similar products continue to increase in popularity among middle school and high school students.⁵⁷

While smoking cessation and health improvement are cited as reasons for vaping among middle-aged and older adults, adolescents and young adults more often cite flavor, enjoyment, peer use, and curiosity as reasons for use.

Adolescents are more likely to report interest in trying a vape product flavored with menthol or fruit than tobacco, and commonly hold the belief that fruit-flavored e-cigarettes are less harmful than tobacco-flavored e-cigarettes.⁵⁸ Harrell et al⁵⁹ polled youth and young adults who used flavored e-cigarettes, and 78% said they would no longer use the product if their preferred flavor were not available. In September 2019, Michigan became the first state to ban the sale of flavored e-cigarettes in stores and online. Similar bills have been introduced in California, Massachusetts, and New York.⁶⁰

Myths and misperceptions abound among youth regarding smoking vs vaping. Young people view regular cigarette smoking negatively, as causing cancer, bad breath, and asthma exacerbations. Meanwhile, they believe marijuana is safer and less addictive than traditional cigarette smoking.⁶¹ Youth exposed to e-cigarette advertisements viewed e-cigarettes as healthier, more enjoyable, “cool,” safe, and fun.⁶¹ The overall public health impact of increasing initiation of smoking, particularly among youth and young adults, should not be underestimated.

SECONDHAND VAPE AND OTHER EXPOSURE RISKS

Cigarette smoking has been banned in many public places, in view of a large body of scientific evidence about the harmful effects of secondhand smoke. Advocates for allowing vaping in public places say that vaping emissions do not harm bystanders, but evidence is insufficient to support this claim.⁶² One study showed that passive exposure to e-cigarette aerosol generated increases in serum levels of cotinine (a nicotine metabolite) similar to those with passive exposure to conventional cigarette smoke.⁵

Accidental nicotine poisoning in children as a result of ingesting e-cigarette liquid is also a major concern,⁶³ particularly with sweet flavors such as bubblegum or cheesecake that may be attractive to children.

Calls to US poison control centers with respect to e-cigarettes and vaping increased from 1 per month in September 2010 to 215 in February 2014, with 51% involving children under age 5.⁶⁴ This trend resulted in the Child Nicotine Poisoning Prevention Act, which passed in 2015 and went into effect in 2016, requiring packaging that is difficult to open for children under age 5.⁵

Device malfunctions or battery failures have led to explosions that have resulted in substantial injuries to users, as well as house and car fires.⁴⁹

HOW DO WE DISCOURAGE ADOLESCENT USE?

There are currently no established treatment approaches for adolescents who have become addicted to vaping. A review of the literature regarding treatment modalities used to address adolescent use of tobacco and marijuana provides insight that options such as nicotine replacement therapy and counseling modalities such as cognitive behavioral therapy may be helpful in treating teen vaping addiction. However, more research is needed to determine the effectiveness of these treatments in youth addicted to vaping.

Given that youth who vape even once are more likely to try other types of tobacco, we recommend that parents and healthcare providers start conversations by asking what the young person has seen or heard about vaping. Young people can also be asked what they think the school’s response should be: Do they think vaping should be banned in public places, as cigarettes have been banned? What about the carbon footprint? What are their thoughts on the plastic waste, batteries, and other toxins generated by the e-cigarette industry?

New US laws ban the sale of e-cigarettes and vaping devices to minors in stores and online. These policies are modeled in many cases on environmental control policies that have been previously employed to reduce tobacco use, particularly by youth. For example, changing laws to mandate sales only to individuals age 21 and older in all states can help to decrease access to these products among middle school and high school students.

As with tobacco cessation, education will not be enough. Support of legislation that bans vaping in public places, increases pricing to discourage adolescent use, and other measures used successfully to decrease conventional cigarette smoking can be deployed to decrease the public health impact of e-cigarettes. We recommend further regulation of specific harmful chemicals and clear, detailed ingredient labeling to increase consumer understanding of the risks associated with these products. Additionally, we recommend eliminating flavored e-cigarettes, which are the most appealing type for young users, and raising prices of e-cigarettes and similar products to discourage use by youth.

If current cigarette smokers want to use e-cigarettes to quit, we recommend that clinicians counsel them to eventually completely stop use of traditional cigarettes and switch to using e-cigarettes, instead of becoming a dual user of both types of products or using e-cigarettes indefinitely. After making that switch, they should then work to gradually taper usage and nicotine addiction by reducing the amount of nicotine in the e-liquid. Clinicians should ask patients about use of e-cigarettes and vaping devices specifically, and should counsel nonsmokers to avoid initiation of use.

EVIDENCE OF HARM CONTINUES TO EMERGE

Data about respiratory effects, secondhand exposure, and long-term smoking cessation efficacy are still limited, and it remains as yet unknown what combinations of solvents, flavorings, and nicotine in a given e-liquid will result in the most harmful or least harmful effects. In addition, while much of the information about the safety of these components has been obtained using in vitro or mouse models, increasing reports of serious respiratory illness and rising numbers of deaths linked to vaping make it clear that these findings likely translate to harmful effects in humans.

E-cigarettes may ultimately prove to be less harmful than traditional cigarettes, but it seems likely that with further time and research, serious health risks of e-cigarette use will continue to emerge.

Electronic cigarettes and other “vaping” devices have been increasing in popularity among youth and adults since their introduction in the US market in 2007.¹ This increase is partially driven by a public perception that vaping is harmless, or at least less harmful than cigarette smoking.² Vaping fans also argue that current smokers can use vaping as nicotine replacement therapy to help them quit smoking.³

We disagree. Research on the health effects of vaping, though still limited, is accumulating rapidly and making it increasingly clear that this habit is far from harmless. For youth, it is a gateway to addiction to nicotine and other substances. Whether it can help people quit smoking remains to be seen. And recent months have seen reports of serious respiratory illnesses and even deaths linked to vaping.⁴

In December 2016, the US Surgeon General warned that e-cigarette use among youth and young adults in the United States represents a “major public health concern,”⁵ and that more adolescents and young adults are now vaping than smoking conventional tobacco products.

This article reviews the issue of vaping in the United States, as well as available evidence regarding its safety.

YOUTH AT RISK

Retail sales of e-cigarettes and vaping devices approach an annual $7 billion.⁶ A 2014–2015 survey found that 2.4% of the general US population were current users of e-cigarettes, and 8.5% had tried them at least once.³

In 2014, for the first time, e-cigarette use became more common among US youth than traditional cigarettes.⁵

The odds of taking up vaping are higher among minority youth in the United States, particularly Hispanics.⁹ This trend is particularly worrisome because several longitudinal studies have shown that adolescents who use e-cigarettes are 3 times as likely to eventually become smokers of traditional cigarettes compared with adolescents who do not use e-cigarettes.^10–12

If US youth continue smoking at the current rate, 5.6 million of the current population under age 18, or 1 of every 13, will die early of a smoking-related illness.¹³ 

RECENT OUTBREAK OF VAPING-ASSOCIATED LUNG INJURY

As of November 5, 2019, there had been 2,051 cases of vaping-associated lung injury in 49 states (all except Alaska), the District of Columbia, and 1 US territory reported to the US Centers for Disease Control and Prevention (CDC), with 39 confirmed deaths.⁴ The reported cases include respiratory injury including acute eosinophilic pneumonia, organizing pneumonia, acute respiratory distress syndrome, and hypersensitivity pneumonitis.¹⁴

Most of these patients had been vaping tetrahydrocannabinol (THC), though many used both nicotine- and THC-containing products, and others used products containing nicotine exclusively.⁴ Thus, it is difficult to identify the exact substance or substances that may be contributing to this sudden outbreak among vape users, and many different product sources are currently under investigation.

One substance that may be linked to the epidemic is vitamin E acetate, which the New York State Department of Health has detected in high levels in cannabis vaping cartridges used by patients who developed lung injury.¹⁵ The US Food and Drug Administration (FDA) is continuing to analyze vape cartridge samples submitted by affected patients to look for other chemicals that can contribute to the development of serious pulmonary illness.

Source: The US Food and Drug Administration

Vape pens consist of similar elements but are not necessarily similar in appearance to a conventional cigarette, and may look more like a pen or a USB flash drive. In fact, the Juul device is recharged by plugging it into a USB port.

Vaping devices have many street names, including e-cigs, e-hookahs, vape pens, mods, vapes, and tank systems.

The first US patent application for a device resembling a modern e-cigarette was filed in 1963, but the product never made it to the market.¹⁶ Instead, the first commercially successful e-cigarette was created in Beijing in 2003 and introduced to US markets in 2007.

Newer-generation devices have larger batteries and can heat the liquid to higher temperatures, releasing more nicotine and forming additional toxicants such as formaldehyde. Devices lack standardization in terms of design, capacity for safely holding e-liquid, packaging of the e-liquid, and features designed to minimize hazards of use.

Not just nicotine

Many devices are designed for use with other drugs, including THC.¹⁷ In a 2018 study, 10.9% of college students reported vaping marijuana in the past 30 days, up from 5.2% in 2017.¹⁸

Other substances are being vaped as well.¹⁹ In theory, any heat-stable psychoactive recreational drug could be aerosolized and vaped. There are increasing reports of e-liquids containing recreational drugs such as synthetic cannabinoid receptor agonists, crack cocaine, LSD, and methamphetamine.¹⁷

Freedom, rebellion, glamour

Sales have risen rapidly since 2007 with widespread advertising on television and in print publications for popular brands, often featuring celebrities.²⁰ Spending on advertising for e-cigarettes and vape devices rose from $6.4 million in 2011 to $115 million in 2014—and that was before the advent of Juul (see below).²¹

Marketing campaigns for vaping devices mimic the themes previously used successfully by the tobacco industry, eg, freedom, rebellion, and glamour. They also make unsubstantiated claims about health benefits and smoking cessation, though initial websites contained endorsements from physicians, similar to the strategies of tobacco companies in old cigarette ads. Cigarette ads have been prohibited since 1971—but not e-cigarette ads. Moreover, vaping products appear as product placements in television shows and movies, with advocacy groups on social media.²²

By law, buyers have to be 18 or 21

Vaping devices can be purchased at vape shops, convenience stores, gas stations, and over the Internet; up to 50% of sales are conducted online.²⁴

Fruit flavors are popular

Zhu et al²⁵ estimated that 7,700 unique vaping flavors exist, with fruit and candy flavors predominating. The most popular flavors are tobacco and mint, followed by fruit, dessert and candy flavors, alcoholic flavors (strawberry daiquiri, margarita), and food flavors.²⁵ These flavors have been associated with higher usage in youth, leading to increased risk of nicotine addiction.²⁶

WHAT IS JUUL?

The Juul device (Juul Labs, www.juul.com) was developed in 2015 by 2 Stanford University graduates. Their goal was to produce a more satisfying and cigarette-like vaping experience, specifically by increasing the amount of nicotine delivered while maintaining smooth and pleasant inhalation. They created an e-liquid that could be vaporized effectively at lower temperatures.²⁷

While more than 400 brands of vaping devices are currently available in the United States,³ Juul has held the largest market share since 2017,²⁸ an estimated 72.1% as of August 2018.²⁹ The surge in popularity of this particular brand is attributed to its trendy design that is similar in size and appearance to a USB flash drive,²⁹ and its offering of sweet flavors such as “crème brûlée” and “cool mint.”

On April 24, 2018, in view of growing concern about the popularity of Juul products among youth, the FDA requested that the company submit documents regarding its marketing tactics, as well as research on the effects of this marketing on product design and public health impact, and information about adverse experiences and complaints.³⁰ The company was forced to change its marketing to appeal less to youth. Now it offers only 3 flavors: “Virginia tobacco,” “classic tobacco,” and “menthol,” although off-brand pods containing a variety of flavors are still available. And some pods are refillable, so users can essentially vape any substance they want.

Although the Juul device delivers a strong dose of nicotine, it is small and therefore easy to hide from parents and teachers, and widespread use has been reported among youth in middle and high schools. Hoodies, hemp jewelry, and backpacks have been designed to hide the devices and allow for easy, hands-free use. YouTube searches for terms such as “Juul,” “hiding Juul at school,” and “Juul in class,” yield thousands of results.³¹ A 2017 survey reported that 8% of Americans age 15 to 24 had used Juul in the month prior to the survey.³² “To juul” has become a verb.

Each Juul starter kit contains the rechargeable inhalation device plus 4 flavored pods. In the United States, each Juul pod contains nearly as much nicotine as 1 pack of 20 cigarettes in a concentration of 3% or 5%. (Israel and Europe have forced the company to replace the 5% nicotine pods with 1.7% nicotine pods.³³) A starter kit costs $49.99, and additional packs of 4 flavored liquid cartridges or pods cost $15.99.³⁴ Other brands of vape pens cost between $15 and $35, and 10-mL bottles of e-liquid cost approximately $⁷.

What is ‘dripping’?

Hard-core vapers seeking a more intense experience are taking their vaping devices apart and modifying them for “dripping,” ie, directly dripping vape liquids onto the heated coils for inhalation. In a survey, 1 in 4 high school students using vape devices also used them for dripping, citing desires for a thicker cloud of vapor, more intense flavor, “a stronger throat hit,” curiosity, and other reasons.³⁵ Dripping involves higher temperatures, which leads to higher amounts of nicotine delivered, along with more formaldehyde, acetaldehyde, and acetone (see below).³⁶

Studies of vape liquids consistently confirm the presence of toxic substances in the resulting vape aerosol.^37–40 Depending on the combination of flavorings and solvents in a given e-liquid, a variety of chemicals can be detected in the aerosol from various vaping devices. Chemicals that may be detected include known irritants of respiratory mucosa, as well as various carcinogens. The list includes:

• Organic volatile compounds such as propylene glycol, glycerin, and toluene
• Aldehydes such as formaldehyde (released when propylene glycol is heated to high temperatures), acetaldehyde, and benzaldehyde
• Acetone and acrolein
• Carcinogenic nitrosamines
• Polycyclic aromatic hydrocarbons
• Particulate matter
• Metals including chromium, cadmium, nickel, and lead; and particles of copper, nickel, and silver have been found in electronic nicotine delivery system aerosol in higher levels than in conventional cigarette smoke.⁴¹

The specific chemicals detected can vary greatly between brands, even when the flavoring and nicotine content are equivalent, which frequently results in inconsistent and conflicting study findings. The chemicals detected also vary with the voltage or power used to generate the aerosol. Different flavors may carry varying levels of risk; for example, mint- and menthol-flavored e-cigarettes were shown to expose users to dangerous levels of pulegone, a carcinogenic compound banned as a food additive in 2018.⁴² The concentrations of some of these chemicals are sufficiently high to be of toxicologic concern; for example, one study reported the presence of benzaldehyde in e-cigarette aerosol at twice the workplace exposure limit.⁴³

Biologic effects

In an in vitro study,⁴⁴ 57% of e-liquids studied were found to be cytotoxic to human pulmonary fibroblasts, lung epithelial cells, and human embryonic stem cells. Fruit-flavored e-liquids in particular caused a significant increase in DNA fragmentation. Cell cultures treated with e-cigarette liquids showed increased oxidative stress, reduced cell proliferation, and increased DNA damage,⁴⁴ which may have implications for carcinogenic risk.

In another study,⁴⁵ exposure to e-cigarette aerosol as well as conventional cigarette smoke resulted in suppression of genes related to immune and inflammatory response in respiratory epithelial cells. All genes with decreased expression after exposure to conventional cigarette smoke also showed decreased expression with exposure to e-cigarette smoke, which the study authors suggested could lead to immune suppression at the level of the nasal mucosa. Diacetyl and acetoin, chemicals found in certain flavorings, have been linked to bronchiolitis obliterans, or “popcorn lung.”⁴⁶

Nicotine is not benign

The nicotine itself in many vaping liquids should also not be underestimated. Nicotine has harmful neurocognitive effects and addictive properties, particularly in the developing brains of adolescents and young adults.⁴⁷ Nicotine exposure during adolescence negatively affects memory, attention, and emotional regulation,⁴⁸ as well as executive functioning, reward processing, and learning.⁴⁹

The brain undergoes major structural remodeling in adolescence, and nicotine acetylcholine receptors regulate neural maturation. Early exposure to nicotine disrupts this process, leading to poor executive functioning, difficulty learning, decreased memory, and issues with reward processing.

Fetal exposure, if nicotine products are used during pregnancy, has also been linked to adverse consequences such as deficits in attention and cognition, behavioral effects, and sudden infant death syndrome.⁵

Much to learn about toxicity

Partly because vaping devices have been available to US consumers only since 2007, limited evidence is available regarding the long-term effects of exposure to the aerosol from these devices in humans.¹ Many of the studies mentioned above were in vitro studies or conducted in mouse models. Differences in device design and the composition of the e-liquid among device brands pose a challenge for developing well-designed studies of the long-term health effects of e-cigarette and vape use. Additionally, devices may have different health impacts when used to vape cannabis or other drugs besides nicotine, which requires further investigation.

E-CIGARETTES AND SMOKING CESSATION

Conventional cigarette smoking is a major public health threat, as tobacco use is responsible for 480,000 deaths annually in the United States.⁵⁰

And smoking is extremely difficult to quit: as many as 80% of smokers who attempt to quit resume smoking within the first month.⁵¹ The chance of successfully quitting improves by over 50% if the individual undergoes nicotine replacement therapy, and it improves even more with counseling.⁵⁰

There are currently 5 types of FDA-approved nicotine replacement therapy products (gum, patch, lozenge, inhaler, nasal spray) to help with smoking cessation. In addition, 2 non-nicotine prescription drugs (varenicline and bupropion) have been approved for treating tobacco dependence.

Can vaping devices be added to the list of nicotine replacement therapy products? Although some manufacturers try to brand their devices as smoking cessation aids, in one study,⁵² one-third of e-cigarette users said they had either never used conventional cigarettes or had formerly smoked them.

Bullen et al⁵³ randomized smokers interested in quitting to receive either e-cigarettes, nicotine patches, or placebo (nicotine-free) e-cigarettes and followed them for 6 months. Rates of tobacco cessation were less than predicted for the entire study population, resulting in insufficient power to determine the superiority of any single method, but the study authors concluded that nicotine e-cigarettes were “modestly effective” at helping smokers quit, and that abstinence rates may be similar to those with nicotine patches.⁵³

Hajek et al⁵⁴ randomized 886 smokers to e-cigarette or nicotine replacement products of their choice. After 1 year, 18% of e-cigarette users had stopped smoking, compared with  9.9% of nicotine replacement product users. However, 80% of the e-cigarette users were still using e-cigarettes after 1 year, while only 9% of nicotine replacement product users were still using nicotine replacement therapy products after 1 year.

While quitting conventional cigarette smoking altogether has widely established health benefits, little is known about the health benefits of transitioning from conventional cigarette smoking to reduced conventional cigarette smoking with concomitant use of e-cigarettes.

Campagna et al⁵⁵ found no beneficial health effects in smokers who partially substituted conventional cigarettes for e-cigarettes.

Many studies found that smokers use e-cigarettes to maintain their habit instead of quitting entirely.⁵⁶ It has been suggested that any slight increase in effectiveness in smoking cessation by using e-cigarettes compared with other nicotine replacement products could be linked to satisfying of the habitual smoking actions, such as inhaling and bringing the hand to the mouth,²⁴ which are absent when using other nicotine replacement methods such as a nicotine patch.

As with safety information, long-term outcomes regarding the use of vape devices for smoking cessation have not been yet established, as this option is still relatively new.

Another worrisome trend involving electronic nicotine delivery systems is their marketing and branding, which appear to be aimed directly at adolescents and young adults. Juul and other similar products cannot be sold to anyone under the age of 18 (or 21 in 18 states, including California, Massachusetts, New York, and now Ohio). Despite this, Juul and similar products continue to increase in popularity among middle school and high school students.⁵⁷

While smoking cessation and health improvement are cited as reasons for vaping among middle-aged and older adults, adolescents and young adults more often cite flavor, enjoyment, peer use, and curiosity as reasons for use.

Adolescents are more likely to report interest in trying a vape product flavored with menthol or fruit than tobacco, and commonly hold the belief that fruit-flavored e-cigarettes are less harmful than tobacco-flavored e-cigarettes.⁵⁸ Harrell et al⁵⁹ polled youth and young adults who used flavored e-cigarettes, and 78% said they would no longer use the product if their preferred flavor were not available. In September 2019, Michigan became the first state to ban the sale of flavored e-cigarettes in stores and online. Similar bills have been introduced in California, Massachusetts, and New York.⁶⁰

Myths and misperceptions abound among youth regarding smoking vs vaping. Young people view regular cigarette smoking negatively, as causing cancer, bad breath, and asthma exacerbations. Meanwhile, they believe marijuana is safer and less addictive than traditional cigarette smoking.⁶¹ Youth exposed to e-cigarette advertisements viewed e-cigarettes as healthier, more enjoyable, “cool,” safe, and fun.⁶¹ The overall public health impact of increasing initiation of smoking, particularly among youth and young adults, should not be underestimated.

SECONDHAND VAPE AND OTHER EXPOSURE RISKS

Cigarette smoking has been banned in many public places, in view of a large body of scientific evidence about the harmful effects of secondhand smoke. Advocates for allowing vaping in public places say that vaping emissions do not harm bystanders, but evidence is insufficient to support this claim.⁶² One study showed that passive exposure to e-cigarette aerosol generated increases in serum levels of cotinine (a nicotine metabolite) similar to those with passive exposure to conventional cigarette smoke.⁵

Accidental nicotine poisoning in children as a result of ingesting e-cigarette liquid is also a major concern,⁶³ particularly with sweet flavors such as bubblegum or cheesecake that may be attractive to children.

Calls to US poison control centers with respect to e-cigarettes and vaping increased from 1 per month in September 2010 to 215 in February 2014, with 51% involving children under age 5.⁶⁴ This trend resulted in the Child Nicotine Poisoning Prevention Act, which passed in 2015 and went into effect in 2016, requiring packaging that is difficult to open for children under age 5.⁵

Device malfunctions or battery failures have led to explosions that have resulted in substantial injuries to users, as well as house and car fires.⁴⁹

HOW DO WE DISCOURAGE ADOLESCENT USE?

There are currently no established treatment approaches for adolescents who have become addicted to vaping. A review of the literature regarding treatment modalities used to address adolescent use of tobacco and marijuana provides insight that options such as nicotine replacement therapy and counseling modalities such as cognitive behavioral therapy may be helpful in treating teen vaping addiction. However, more research is needed to determine the effectiveness of these treatments in youth addicted to vaping.

Given that youth who vape even once are more likely to try other types of tobacco, we recommend that parents and healthcare providers start conversations by asking what the young person has seen or heard about vaping. Young people can also be asked what they think the school’s response should be: Do they think vaping should be banned in public places, as cigarettes have been banned? What about the carbon footprint? What are their thoughts on the plastic waste, batteries, and other toxins generated by the e-cigarette industry?

New US laws ban the sale of e-cigarettes and vaping devices to minors in stores and online. These policies are modeled in many cases on environmental control policies that have been previously employed to reduce tobacco use, particularly by youth. For example, changing laws to mandate sales only to individuals age 21 and older in all states can help to decrease access to these products among middle school and high school students.

As with tobacco cessation, education will not be enough. Support of legislation that bans vaping in public places, increases pricing to discourage adolescent use, and other measures used successfully to decrease conventional cigarette smoking can be deployed to decrease the public health impact of e-cigarettes. We recommend further regulation of specific harmful chemicals and clear, detailed ingredient labeling to increase consumer understanding of the risks associated with these products. Additionally, we recommend eliminating flavored e-cigarettes, which are the most appealing type for young users, and raising prices of e-cigarettes and similar products to discourage use by youth.

If current cigarette smokers want to use e-cigarettes to quit, we recommend that clinicians counsel them to eventually completely stop use of traditional cigarettes and switch to using e-cigarettes, instead of becoming a dual user of both types of products or using e-cigarettes indefinitely. After making that switch, they should then work to gradually taper usage and nicotine addiction by reducing the amount of nicotine in the e-liquid. Clinicians should ask patients about use of e-cigarettes and vaping devices specifically, and should counsel nonsmokers to avoid initiation of use.

EVIDENCE OF HARM CONTINUES TO EMERGE

Data about respiratory effects, secondhand exposure, and long-term smoking cessation efficacy are still limited, and it remains as yet unknown what combinations of solvents, flavorings, and nicotine in a given e-liquid will result in the most harmful or least harmful effects. In addition, while much of the information about the safety of these components has been obtained using in vitro or mouse models, increasing reports of serious respiratory illness and rising numbers of deaths linked to vaping make it clear that these findings likely translate to harmful effects in humans.

E-cigarettes may ultimately prove to be less harmful than traditional cigarettes, but it seems likely that with further time and research, serious health risks of e-cigarette use will continue to emerge.

Electronic cigarettes and other “vaping” devices have been increasing in popularity among youth and adults since their introduction in the US market in 2007.¹ This increase is partially driven by a public perception that vaping is harmless, or at least less harmful than cigarette smoking.² Vaping fans also argue that current smokers can use vaping as nicotine replacement therapy to help them quit smoking.³

We disagree. Research on the health effects of vaping, though still limited, is accumulating rapidly and making it increasingly clear that this habit is far from harmless. For youth, it is a gateway to addiction to nicotine and other substances. Whether it can help people quit smoking remains to be seen. And recent months have seen reports of serious respiratory illnesses and even deaths linked to vaping.⁴

In December 2016, the US Surgeon General warned that e-cigarette use among youth and young adults in the United States represents a “major public health concern,”⁵ and that more adolescents and young adults are now vaping than smoking conventional tobacco products.

This article reviews the issue of vaping in the United States, as well as available evidence regarding its safety.

YOUTH AT RISK

Retail sales of e-cigarettes and vaping devices approach an annual $7 billion.⁶ A 2014–2015 survey found that 2.4% of the general US population were current users of e-cigarettes, and 8.5% had tried them at least once.³

In 2014, for the first time, e-cigarette use became more common among US youth than traditional cigarettes.⁵

The odds of taking up vaping are higher among minority youth in the United States, particularly Hispanics.⁹ This trend is particularly worrisome because several longitudinal studies have shown that adolescents who use e-cigarettes are 3 times as likely to eventually become smokers of traditional cigarettes compared with adolescents who do not use e-cigarettes.^10–12

If US youth continue smoking at the current rate, 5.6 million of the current population under age 18, or 1 of every 13, will die early of a smoking-related illness.¹³ 

RECENT OUTBREAK OF VAPING-ASSOCIATED LUNG INJURY

As of November 5, 2019, there had been 2,051 cases of vaping-associated lung injury in 49 states (all except Alaska), the District of Columbia, and 1 US territory reported to the US Centers for Disease Control and Prevention (CDC), with 39 confirmed deaths.⁴ The reported cases include respiratory injury including acute eosinophilic pneumonia, organizing pneumonia, acute respiratory distress syndrome, and hypersensitivity pneumonitis.¹⁴

Most of these patients had been vaping tetrahydrocannabinol (THC), though many used both nicotine- and THC-containing products, and others used products containing nicotine exclusively.⁴ Thus, it is difficult to identify the exact substance or substances that may be contributing to this sudden outbreak among vape users, and many different product sources are currently under investigation.

One substance that may be linked to the epidemic is vitamin E acetate, which the New York State Department of Health has detected in high levels in cannabis vaping cartridges used by patients who developed lung injury.¹⁵ The US Food and Drug Administration (FDA) is continuing to analyze vape cartridge samples submitted by affected patients to look for other chemicals that can contribute to the development of serious pulmonary illness.

Source: The US Food and Drug Administration

Vape pens consist of similar elements but are not necessarily similar in appearance to a conventional cigarette, and may look more like a pen or a USB flash drive. In fact, the Juul device is recharged by plugging it into a USB port.

Vaping devices have many street names, including e-cigs, e-hookahs, vape pens, mods, vapes, and tank systems.

The first US patent application for a device resembling a modern e-cigarette was filed in 1963, but the product never made it to the market.¹⁶ Instead, the first commercially successful e-cigarette was created in Beijing in 2003 and introduced to US markets in 2007.

Newer-generation devices have larger batteries and can heat the liquid to higher temperatures, releasing more nicotine and forming additional toxicants such as formaldehyde. Devices lack standardization in terms of design, capacity for safely holding e-liquid, packaging of the e-liquid, and features designed to minimize hazards of use.

Not just nicotine

Many devices are designed for use with other drugs, including THC.¹⁷ In a 2018 study, 10.9% of college students reported vaping marijuana in the past 30 days, up from 5.2% in 2017.¹⁸

Other substances are being vaped as well.¹⁹ In theory, any heat-stable psychoactive recreational drug could be aerosolized and vaped. There are increasing reports of e-liquids containing recreational drugs such as synthetic cannabinoid receptor agonists, crack cocaine, LSD, and methamphetamine.¹⁷

Freedom, rebellion, glamour

Sales have risen rapidly since 2007 with widespread advertising on television and in print publications for popular brands, often featuring celebrities.²⁰ Spending on advertising for e-cigarettes and vape devices rose from $6.4 million in 2011 to $115 million in 2014—and that was before the advent of Juul (see below).²¹

Marketing campaigns for vaping devices mimic the themes previously used successfully by the tobacco industry, eg, freedom, rebellion, and glamour. They also make unsubstantiated claims about health benefits and smoking cessation, though initial websites contained endorsements from physicians, similar to the strategies of tobacco companies in old cigarette ads. Cigarette ads have been prohibited since 1971—but not e-cigarette ads. Moreover, vaping products appear as product placements in television shows and movies, with advocacy groups on social media.²²

By law, buyers have to be 18 or 21

Vaping devices can be purchased at vape shops, convenience stores, gas stations, and over the Internet; up to 50% of sales are conducted online.²⁴

Fruit flavors are popular

Zhu et al²⁵ estimated that 7,700 unique vaping flavors exist, with fruit and candy flavors predominating. The most popular flavors are tobacco and mint, followed by fruit, dessert and candy flavors, alcoholic flavors (strawberry daiquiri, margarita), and food flavors.²⁵ These flavors have been associated with higher usage in youth, leading to increased risk of nicotine addiction.²⁶

WHAT IS JUUL?

The Juul device (Juul Labs, www.juul.com) was developed in 2015 by 2 Stanford University graduates. Their goal was to produce a more satisfying and cigarette-like vaping experience, specifically by increasing the amount of nicotine delivered while maintaining smooth and pleasant inhalation. They created an e-liquid that could be vaporized effectively at lower temperatures.²⁷

While more than 400 brands of vaping devices are currently available in the United States,³ Juul has held the largest market share since 2017,²⁸ an estimated 72.1% as of August 2018.²⁹ The surge in popularity of this particular brand is attributed to its trendy design that is similar in size and appearance to a USB flash drive,²⁹ and its offering of sweet flavors such as “crème brûlée” and “cool mint.”

On April 24, 2018, in view of growing concern about the popularity of Juul products among youth, the FDA requested that the company submit documents regarding its marketing tactics, as well as research on the effects of this marketing on product design and public health impact, and information about adverse experiences and complaints.³⁰ The company was forced to change its marketing to appeal less to youth. Now it offers only 3 flavors: “Virginia tobacco,” “classic tobacco,” and “menthol,” although off-brand pods containing a variety of flavors are still available. And some pods are refillable, so users can essentially vape any substance they want.

Although the Juul device delivers a strong dose of nicotine, it is small and therefore easy to hide from parents and teachers, and widespread use has been reported among youth in middle and high schools. Hoodies, hemp jewelry, and backpacks have been designed to hide the devices and allow for easy, hands-free use. YouTube searches for terms such as “Juul,” “hiding Juul at school,” and “Juul in class,” yield thousands of results.³¹ A 2017 survey reported that 8% of Americans age 15 to 24 had used Juul in the month prior to the survey.³² “To juul” has become a verb.

Each Juul starter kit contains the rechargeable inhalation device plus 4 flavored pods. In the United States, each Juul pod contains nearly as much nicotine as 1 pack of 20 cigarettes in a concentration of 3% or 5%. (Israel and Europe have forced the company to replace the 5% nicotine pods with 1.7% nicotine pods.³³) A starter kit costs $49.99, and additional packs of 4 flavored liquid cartridges or pods cost $15.99.³⁴ Other brands of vape pens cost between $15 and $35, and 10-mL bottles of e-liquid cost approximately $⁷.

What is ‘dripping’?

Hard-core vapers seeking a more intense experience are taking their vaping devices apart and modifying them for “dripping,” ie, directly dripping vape liquids onto the heated coils for inhalation. In a survey, 1 in 4 high school students using vape devices also used them for dripping, citing desires for a thicker cloud of vapor, more intense flavor, “a stronger throat hit,” curiosity, and other reasons.³⁵ Dripping involves higher temperatures, which leads to higher amounts of nicotine delivered, along with more formaldehyde, acetaldehyde, and acetone (see below).³⁶

Studies of vape liquids consistently confirm the presence of toxic substances in the resulting vape aerosol.^37–40 Depending on the combination of flavorings and solvents in a given e-liquid, a variety of chemicals can be detected in the aerosol from various vaping devices. Chemicals that may be detected include known irritants of respiratory mucosa, as well as various carcinogens. The list includes:

• Organic volatile compounds such as propylene glycol, glycerin, and toluene
• Aldehydes such as formaldehyde (released when propylene glycol is heated to high temperatures), acetaldehyde, and benzaldehyde
• Acetone and acrolein
• Carcinogenic nitrosamines
• Polycyclic aromatic hydrocarbons
• Particulate matter
• Metals including chromium, cadmium, nickel, and lead; and particles of copper, nickel, and silver have been found in electronic nicotine delivery system aerosol in higher levels than in conventional cigarette smoke.⁴¹

The specific chemicals detected can vary greatly between brands, even when the flavoring and nicotine content are equivalent, which frequently results in inconsistent and conflicting study findings. The chemicals detected also vary with the voltage or power used to generate the aerosol. Different flavors may carry varying levels of risk; for example, mint- and menthol-flavored e-cigarettes were shown to expose users to dangerous levels of pulegone, a carcinogenic compound banned as a food additive in 2018.⁴² The concentrations of some of these chemicals are sufficiently high to be of toxicologic concern; for example, one study reported the presence of benzaldehyde in e-cigarette aerosol at twice the workplace exposure limit.⁴³

Biologic effects

In an in vitro study,⁴⁴ 57% of e-liquids studied were found to be cytotoxic to human pulmonary fibroblasts, lung epithelial cells, and human embryonic stem cells. Fruit-flavored e-liquids in particular caused a significant increase in DNA fragmentation. Cell cultures treated with e-cigarette liquids showed increased oxidative stress, reduced cell proliferation, and increased DNA damage,⁴⁴ which may have implications for carcinogenic risk.

In another study,⁴⁵ exposure to e-cigarette aerosol as well as conventional cigarette smoke resulted in suppression of genes related to immune and inflammatory response in respiratory epithelial cells. All genes with decreased expression after exposure to conventional cigarette smoke also showed decreased expression with exposure to e-cigarette smoke, which the study authors suggested could lead to immune suppression at the level of the nasal mucosa. Diacetyl and acetoin, chemicals found in certain flavorings, have been linked to bronchiolitis obliterans, or “popcorn lung.”⁴⁶

Nicotine is not benign

The nicotine itself in many vaping liquids should also not be underestimated. Nicotine has harmful neurocognitive effects and addictive properties, particularly in the developing brains of adolescents and young adults.⁴⁷ Nicotine exposure during adolescence negatively affects memory, attention, and emotional regulation,⁴⁸ as well as executive functioning, reward processing, and learning.⁴⁹

The brain undergoes major structural remodeling in adolescence, and nicotine acetylcholine receptors regulate neural maturation. Early exposure to nicotine disrupts this process, leading to poor executive functioning, difficulty learning, decreased memory, and issues with reward processing.

Fetal exposure, if nicotine products are used during pregnancy, has also been linked to adverse consequences such as deficits in attention and cognition, behavioral effects, and sudden infant death syndrome.⁵

Much to learn about toxicity

Partly because vaping devices have been available to US consumers only since 2007, limited evidence is available regarding the long-term effects of exposure to the aerosol from these devices in humans.¹ Many of the studies mentioned above were in vitro studies or conducted in mouse models. Differences in device design and the composition of the e-liquid among device brands pose a challenge for developing well-designed studies of the long-term health effects of e-cigarette and vape use. Additionally, devices may have different health impacts when used to vape cannabis or other drugs besides nicotine, which requires further investigation.

E-CIGARETTES AND SMOKING CESSATION

Conventional cigarette smoking is a major public health threat, as tobacco use is responsible for 480,000 deaths annually in the United States.⁵⁰

And smoking is extremely difficult to quit: as many as 80% of smokers who attempt to quit resume smoking within the first month.⁵¹ The chance of successfully quitting improves by over 50% if the individual undergoes nicotine replacement therapy, and it improves even more with counseling.⁵⁰

There are currently 5 types of FDA-approved nicotine replacement therapy products (gum, patch, lozenge, inhaler, nasal spray) to help with smoking cessation. In addition, 2 non-nicotine prescription drugs (varenicline and bupropion) have been approved for treating tobacco dependence.

Can vaping devices be added to the list of nicotine replacement therapy products? Although some manufacturers try to brand their devices as smoking cessation aids, in one study,⁵² one-third of e-cigarette users said they had either never used conventional cigarettes or had formerly smoked them.

Bullen et al⁵³ randomized smokers interested in quitting to receive either e-cigarettes, nicotine patches, or placebo (nicotine-free) e-cigarettes and followed them for 6 months. Rates of tobacco cessation were less than predicted for the entire study population, resulting in insufficient power to determine the superiority of any single method, but the study authors concluded that nicotine e-cigarettes were “modestly effective” at helping smokers quit, and that abstinence rates may be similar to those with nicotine patches.⁵³

Hajek et al⁵⁴ randomized 886 smokers to e-cigarette or nicotine replacement products of their choice. After 1 year, 18% of e-cigarette users had stopped smoking, compared with  9.9% of nicotine replacement product users. However, 80% of the e-cigarette users were still using e-cigarettes after 1 year, while only 9% of nicotine replacement product users were still using nicotine replacement therapy products after 1 year.

While quitting conventional cigarette smoking altogether has widely established health benefits, little is known about the health benefits of transitioning from conventional cigarette smoking to reduced conventional cigarette smoking with concomitant use of e-cigarettes.

Campagna et al⁵⁵ found no beneficial health effects in smokers who partially substituted conventional cigarettes for e-cigarettes.

Many studies found that smokers use e-cigarettes to maintain their habit instead of quitting entirely.⁵⁶ It has been suggested that any slight increase in effectiveness in smoking cessation by using e-cigarettes compared with other nicotine replacement products could be linked to satisfying of the habitual smoking actions, such as inhaling and bringing the hand to the mouth,²⁴ which are absent when using other nicotine replacement methods such as a nicotine patch.

As with safety information, long-term outcomes regarding the use of vape devices for smoking cessation have not been yet established, as this option is still relatively new.

Another worrisome trend involving electronic nicotine delivery systems is their marketing and branding, which appear to be aimed directly at adolescents and young adults. Juul and other similar products cannot be sold to anyone under the age of 18 (or 21 in 18 states, including California, Massachusetts, New York, and now Ohio). Despite this, Juul and similar products continue to increase in popularity among middle school and high school students.⁵⁷

While smoking cessation and health improvement are cited as reasons for vaping among middle-aged and older adults, adolescents and young adults more often cite flavor, enjoyment, peer use, and curiosity as reasons for use.

Adolescents are more likely to report interest in trying a vape product flavored with menthol or fruit than tobacco, and commonly hold the belief that fruit-flavored e-cigarettes are less harmful than tobacco-flavored e-cigarettes.⁵⁸ Harrell et al⁵⁹ polled youth and young adults who used flavored e-cigarettes, and 78% said they would no longer use the product if their preferred flavor were not available. In September 2019, Michigan became the first state to ban the sale of flavored e-cigarettes in stores and online. Similar bills have been introduced in California, Massachusetts, and New York.⁶⁰

Myths and misperceptions abound among youth regarding smoking vs vaping. Young people view regular cigarette smoking negatively, as causing cancer, bad breath, and asthma exacerbations. Meanwhile, they believe marijuana is safer and less addictive than traditional cigarette smoking.⁶¹ Youth exposed to e-cigarette advertisements viewed e-cigarettes as healthier, more enjoyable, “cool,” safe, and fun.⁶¹ The overall public health impact of increasing initiation of smoking, particularly among youth and young adults, should not be underestimated.

SECONDHAND VAPE AND OTHER EXPOSURE RISKS

Cigarette smoking has been banned in many public places, in view of a large body of scientific evidence about the harmful effects of secondhand smoke. Advocates for allowing vaping in public places say that vaping emissions do not harm bystanders, but evidence is insufficient to support this claim.⁶² One study showed that passive exposure to e-cigarette aerosol generated increases in serum levels of cotinine (a nicotine metabolite) similar to those with passive exposure to conventional cigarette smoke.⁵

Accidental nicotine poisoning in children as a result of ingesting e-cigarette liquid is also a major concern,⁶³ particularly with sweet flavors such as bubblegum or cheesecake that may be attractive to children.

Calls to US poison control centers with respect to e-cigarettes and vaping increased from 1 per month in September 2010 to 215 in February 2014, with 51% involving children under age 5.⁶⁴ This trend resulted in the Child Nicotine Poisoning Prevention Act, which passed in 2015 and went into effect in 2016, requiring packaging that is difficult to open for children under age 5.⁵

Device malfunctions or battery failures have led to explosions that have resulted in substantial injuries to users, as well as house and car fires.⁴⁹

HOW DO WE DISCOURAGE ADOLESCENT USE?

There are currently no established treatment approaches for adolescents who have become addicted to vaping. A review of the literature regarding treatment modalities used to address adolescent use of tobacco and marijuana provides insight that options such as nicotine replacement therapy and counseling modalities such as cognitive behavioral therapy may be helpful in treating teen vaping addiction. However, more research is needed to determine the effectiveness of these treatments in youth addicted to vaping.

Given that youth who vape even once are more likely to try other types of tobacco, we recommend that parents and healthcare providers start conversations by asking what the young person has seen or heard about vaping. Young people can also be asked what they think the school’s response should be: Do they think vaping should be banned in public places, as cigarettes have been banned? What about the carbon footprint? What are their thoughts on the plastic waste, batteries, and other toxins generated by the e-cigarette industry?

New US laws ban the sale of e-cigarettes and vaping devices to minors in stores and online. These policies are modeled in many cases on environmental control policies that have been previously employed to reduce tobacco use, particularly by youth. For example, changing laws to mandate sales only to individuals age 21 and older in all states can help to decrease access to these products among middle school and high school students.

As with tobacco cessation, education will not be enough. Support of legislation that bans vaping in public places, increases pricing to discourage adolescent use, and other measures used successfully to decrease conventional cigarette smoking can be deployed to decrease the public health impact of e-cigarettes. We recommend further regulation of specific harmful chemicals and clear, detailed ingredient labeling to increase consumer understanding of the risks associated with these products. Additionally, we recommend eliminating flavored e-cigarettes, which are the most appealing type for young users, and raising prices of e-cigarettes and similar products to discourage use by youth.

If current cigarette smokers want to use e-cigarettes to quit, we recommend that clinicians counsel them to eventually completely stop use of traditional cigarettes and switch to using e-cigarettes, instead of becoming a dual user of both types of products or using e-cigarettes indefinitely. After making that switch, they should then work to gradually taper usage and nicotine addiction by reducing the amount of nicotine in the e-liquid. Clinicians should ask patients about use of e-cigarettes and vaping devices specifically, and should counsel nonsmokers to avoid initiation of use.

EVIDENCE OF HARM CONTINUES TO EMERGE

Data about respiratory effects, secondhand exposure, and long-term smoking cessation efficacy are still limited, and it remains as yet unknown what combinations of solvents, flavorings, and nicotine in a given e-liquid will result in the most harmful or least harmful effects. In addition, while much of the information about the safety of these components has been obtained using in vitro or mouse models, increasing reports of serious respiratory illness and rising numbers of deaths linked to vaping make it clear that these findings likely translate to harmful effects in humans.

E-cigarettes may ultimately prove to be less harmful than traditional cigarettes, but it seems likely that with further time and research, serious health risks of e-cigarette use will continue to emerge.

A 44-year-old woman presents with an 8-year history of intermittent heartburn, and in the past year she has been experiencing her symptoms daily. She says the heartburn is constant and is worse immediately after eating spicy or acidic foods. She says she has had no dysphagia, weight loss, or vomiting. Her symptoms have persisted despite taking a histamine (H)₂-receptor antagonist twice daily plus a proton pump inhibitor (PPI) before breakfast and dinner for more than 3 months.

She has undergone upper endoscopy 3 times in the past 8 years. Each time, the esophagus was normal with a regular Z-line and normal biopsy results from the proximal and distal esophagus.

The patient believes she has severe gastroesophageal reflux disease (GERD) and asks if she is a candidate for fundoplication surgery.

HEARTBURN IS A SYMPTOM; GERD IS A CONDITION

A distinction should be made between heartburn—the symptom of persistent retrosternal burning and discomfort—and gastroesophageal reflux disease—the condition in which reflux of stomach contents causes troublesome symptoms or complications.¹ While many clinicians initially diagnose patients who have heartburn as having GERD, there are many other potential causes of their symptoms.

For patients with persistent heartburn, an empiric trial of a once-daily PPI is usually effective, but one-third of patients continue to have heartburn.^2,3 The most common cause of this PPI-refractory heartburn is functional heartburn, a functional or hypersensitivity disorder of the esophagus.⁴

PATHOPHYSIOLOGY IS POORLY UNDERSTOOD

DIAGNOSTIC EVALUATION

Clinicians have several tests available for diagnosing these conditions.

Upper endoscopy

Upper endoscopy is recommended for patients with heartburn that does not respond to a 3-month trial of a PPI.⁹ Endoscopy is also indicated in any patient who has any of the following “alarm symptoms” that could be due to malignancy or peptic ulcer:

• Dysphagia
• Odynophagia
• Vomiting
• Unexplained weight loss or anemia
• Signs of gastrointestinal bleeding
• Anorexia
• New onset of dyspepsia in a patient over age 60.

During upper endoscopy, the esophagus is evaluated for reflux esophagitis, Barrett esophagus, and other inflammatory disorders such as infectious esophagitis. But even if the esophageal mucosa appears normal, the proximal and distal esophagus should be biopsied to rule out an inflammatory disorder such as eosinophilic or lymphocytic esophagitis.

If endoscopic and esophageal biopsy results are inconclusive, a workup for an esophageal motility disorder is the next step. Dysphagia is the most common symptom of these disorders, although the initial presenting symptom may be heartburn or regurgitation that persists despite PPI therapy.

Manometry is used to test for motility disorders such as achalasia and esophageal spasm.¹⁰ After applying a local anesthetic inside the nares, the clinician inserts a flexible catheter (about 4 mm in diameter) with 36 pressure sensors spaced at 1-cm intervals into the nares and passes it through the esophagus and lower esophageal sphincter. The patient then swallows liquid, and the sensors relay the esophageal response, creating a topographic plot that shows esophageal peristalsis and lower esophageal sphincter relaxation.

Achalasia is identified by incomplete lower esophageal sphincter relaxation combined with 100% failed peristalsis in the body of the esophagus. Esophageal spasms are identified by a shortened distal latency, which corresponds to premature contraction of the esophagus during peristalsis.¹¹

Esophageal pH testing

Measuring esophageal pH levels is an important step to quantify gastroesophageal reflux and determine if symptoms occur during reflux events. According to the updated Porto GERD consensus group recommendations,¹² a pH test is positive if the acid exposure time is greater than 6% of the testing period. Testing the pH differentiates between GERD (abnormal acid exposure), reflux hypersensitivity (normal acid exposure, strong correlation between symptoms and reflux events), and functional heartburn (normal acid exposure, negative correlation between reflux events and symptoms).⁵ For this test, a pH probe is placed in the esophagus transnasally or endoscopically. The probe records esophageal pH levels for 24 to 96 hours in an outpatient setting. Antisecretory therapy needs to be withheld for 7 to 10 days before the test.

Transnasal pH probe. For this approach, a thin catheter is inserted through the nares and advanced until the tip is 5 cm proximal to the lower esophageal sphincter. (The placement is guided by the results of esophageal manometry, which is done immediately before pH catheter placement.) The tube is secured with clear tape on the side of the patient’s face, and the end is connected to a portable recorder that compiles the data. The patient pushes a button on the recorder when experiencing heartburn symptoms. (A nurse instructs the patient on proper procedure.) After 24 hours, the patient either removes the catheter or has the clinic remove it. The pH and symptom data are downloaded and analyzed.

Transnasal pH testing can be combined with impedance measurement, which can detect nonacid reflux or weakly acid reflux. However, the clinical significance of this measurement is unclear, as multiple studies have found total acid exposure time to be a better predictor of response to therapy than weakly acid or nonacid reflux.¹²

Wireless pH probe. This method uses a disposable, catheter-free, capsule device to measure esophageal pH. The capsule, about the size of a gel capsule or pencil eraser, is attached to the patient’s esophageal lining, usually during upper endoscopy. The capsule records pH levels in the lower esophagus for 48 to 96 hours and transmits the data wirelessly to a receiver the patient wears. The patient pushes buttons on the receiver to record symptom-specific data when experiencing heartburn, chest pain, regurgitation, or cough. The capsule detaches from the esophagus spontaneously, generally within 7 days, and is passed out of the body through a bowel movement.

Diagnosing functional heartburn

CASE CONTINUED: NORMAL RESULTS ON TESTING

Based on these results, her condition is diagnosed as functional heartburn, consistent with the Rome IV criteria.⁵

Patient education is key

Patient education about the pathogenesis, natural history, and treatment options is the most important aspect of treating any functional gastrointestinal disorder. This includes the “brain-gut connection” and potential mechanisms of dysregulation. Patient education along with assessment of symptoms should be part of every visit, especially before discussing treatment options.

Patients whose condition is diagnosed as functional heartburn need reassurance that the condition is benign and, in particular, that the risk of progression to esophageal adenocarcinoma is minimal in the absence of Barrett esophagus.¹³ Also important to point out is that the disorder may spontaneously resolve: resolution rates of up to 40% have been reported for other functional gastrointestinal disorders.¹⁴

Antisecretory medications may work for some

A PPI or H₂-receptor antagonist is the most common first-line treatment for heartburn symptoms. Although most patients with functional heartburn experience no improvement in symptoms with an antisecretory agent, a small number report some relief, which suggests that acid-suppression therapy may have an indirect impact on pain modulation in the esophagus.¹⁵ In patients who report symptom relief with an antisecretory agent, we suggest continuing the medication tapered to the lowest effective dose, with repeated reassurance that the medication can be discontinued safely at any time.

Antireflux surgery should be avoided

Antireflux surgery should be avoided in patients with normal pH testing and no objective finding of reflux, as this is associated with worse subjective outcomes than in patients with abnormal pH test results.¹⁶

Neuromodulators

It is important to discuss with patients the concept of neuromodulation, including the fact that antidepressants are often used because of their effects on serotonin and norepinephrine, which decrease visceral hypersensitivity.

The selective serotonin reuptake inhibitor citalopram has been shown to reduce esophageal hypersensitivity,¹⁷ and a tricyclic antidepressant has been shown to improve quality of life.¹⁸ These results have led experts to recommend a trial of a low dose of either type of medication.¹⁹ The dose of tricyclic antidepressant often needs to be increased sequentially every 2 to 4 weeks.

Interestingly, melatonin 6 mg at bedtime has also shown efficacy for functional heartburn, potentially due to its antinociceptive properties.²⁰

Alternative and complementary therapies

Many esophageal centers use cognitive behavioral therapy and hypnotherapy as first-line treatment for functional esophageal disorders. Here again, it is important for the patient to understand the rationale of therapy for functional gastrointestinal disorders, given the stigma in the general population regarding psychotherapy.

Cognitive behavioral therapy has been used for functional gastrointestinal disorders for many years, as it has been shown to modulate visceral perception.²¹ Although published studies are limited, research regarding other functional esophageal disorders suggests that patients who commit to long-term behavioral therapy have had a significant improvement in symptoms.²²

The goal of esophageal-directed behavioral therapy is to promote focused relaxation using deep breathing techniques, which can help patients manage esophageal hypervigilance, especially if symptoms continue despite neuromodulator therapy. Specifically, hypnotherapy has been shown to modulate functional chest pain through the visceral sensory pathway and also to suppress gastric acid secretion.^21,23 A study of a 7-week hypnotherapy program reported significant benefits in heartburn relief and improved quality of life in patients with functional heartburn.²⁴ The data support the use of behavioral therapies as first-line therapy or as adjunctive therapy for patients already taking a neuromodulator.

CASE FOLLOW-UP: IMPROVEMENT WITH TREATMENT

During a follow-up visit, the patient is given several printed resources, including the Rome Foundation article on functional heartburn.⁵ We again emphasize the benign nature of functional heartburn, noting the minimal risk of progression to esophageal adenocarcinoma, as she had no evidence of Barrett esophagus on endoscopy. And we discuss the natural course of functional heartburn, including the spontaneous resolution rate of about 40%.

For treatment, we present her the rationale for using neuromodulators and reassure her that these medications are for treatment of visceral hypersensitivity, not for anxiety or depression. After the discussion, the patient opts to start amitriptyline therapy at 10 mg every night at bedtime, increasing the dose by 10 mg every 2 weeks until symptoms improve, up to 75–100 mg every day.

After 3 months, the patient reports a 90% improvement in symptoms while on amitriptyline 30 mg every night. She is also able to taper her antisecretory medications once symptoms are controlled. We plan to continue amitriptyline at the current dose for 6 to 12 months, then discuss a slow taper to see if her symptoms spontaneously resolve.

A 44-year-old woman presents with an 8-year history of intermittent heartburn, and in the past year she has been experiencing her symptoms daily. She says the heartburn is constant and is worse immediately after eating spicy or acidic foods. She says she has had no dysphagia, weight loss, or vomiting. Her symptoms have persisted despite taking a histamine (H)₂-receptor antagonist twice daily plus a proton pump inhibitor (PPI) before breakfast and dinner for more than 3 months.

She has undergone upper endoscopy 3 times in the past 8 years. Each time, the esophagus was normal with a regular Z-line and normal biopsy results from the proximal and distal esophagus.

The patient believes she has severe gastroesophageal reflux disease (GERD) and asks if she is a candidate for fundoplication surgery.

HEARTBURN IS A SYMPTOM; GERD IS A CONDITION

A distinction should be made between heartburn—the symptom of persistent retrosternal burning and discomfort—and gastroesophageal reflux disease—the condition in which reflux of stomach contents causes troublesome symptoms or complications.¹ While many clinicians initially diagnose patients who have heartburn as having GERD, there are many other potential causes of their symptoms.

For patients with persistent heartburn, an empiric trial of a once-daily PPI is usually effective, but one-third of patients continue to have heartburn.^2,3 The most common cause of this PPI-refractory heartburn is functional heartburn, a functional or hypersensitivity disorder of the esophagus.⁴

PATHOPHYSIOLOGY IS POORLY UNDERSTOOD

DIAGNOSTIC EVALUATION

Clinicians have several tests available for diagnosing these conditions.

Upper endoscopy

Upper endoscopy is recommended for patients with heartburn that does not respond to a 3-month trial of a PPI.⁹ Endoscopy is also indicated in any patient who has any of the following “alarm symptoms” that could be due to malignancy or peptic ulcer:

• Dysphagia
• Odynophagia
• Vomiting
• Unexplained weight loss or anemia
• Signs of gastrointestinal bleeding
• Anorexia
• New onset of dyspepsia in a patient over age 60.

During upper endoscopy, the esophagus is evaluated for reflux esophagitis, Barrett esophagus, and other inflammatory disorders such as infectious esophagitis. But even if the esophageal mucosa appears normal, the proximal and distal esophagus should be biopsied to rule out an inflammatory disorder such as eosinophilic or lymphocytic esophagitis.

If endoscopic and esophageal biopsy results are inconclusive, a workup for an esophageal motility disorder is the next step. Dysphagia is the most common symptom of these disorders, although the initial presenting symptom may be heartburn or regurgitation that persists despite PPI therapy.

Manometry is used to test for motility disorders such as achalasia and esophageal spasm.¹⁰ After applying a local anesthetic inside the nares, the clinician inserts a flexible catheter (about 4 mm in diameter) with 36 pressure sensors spaced at 1-cm intervals into the nares and passes it through the esophagus and lower esophageal sphincter. The patient then swallows liquid, and the sensors relay the esophageal response, creating a topographic plot that shows esophageal peristalsis and lower esophageal sphincter relaxation.

Achalasia is identified by incomplete lower esophageal sphincter relaxation combined with 100% failed peristalsis in the body of the esophagus. Esophageal spasms are identified by a shortened distal latency, which corresponds to premature contraction of the esophagus during peristalsis.¹¹

Esophageal pH testing

Measuring esophageal pH levels is an important step to quantify gastroesophageal reflux and determine if symptoms occur during reflux events. According to the updated Porto GERD consensus group recommendations,¹² a pH test is positive if the acid exposure time is greater than 6% of the testing period. Testing the pH differentiates between GERD (abnormal acid exposure), reflux hypersensitivity (normal acid exposure, strong correlation between symptoms and reflux events), and functional heartburn (normal acid exposure, negative correlation between reflux events and symptoms).⁵ For this test, a pH probe is placed in the esophagus transnasally or endoscopically. The probe records esophageal pH levels for 24 to 96 hours in an outpatient setting. Antisecretory therapy needs to be withheld for 7 to 10 days before the test.

Transnasal pH probe. For this approach, a thin catheter is inserted through the nares and advanced until the tip is 5 cm proximal to the lower esophageal sphincter. (The placement is guided by the results of esophageal manometry, which is done immediately before pH catheter placement.) The tube is secured with clear tape on the side of the patient’s face, and the end is connected to a portable recorder that compiles the data. The patient pushes a button on the recorder when experiencing heartburn symptoms. (A nurse instructs the patient on proper procedure.) After 24 hours, the patient either removes the catheter or has the clinic remove it. The pH and symptom data are downloaded and analyzed.

Transnasal pH testing can be combined with impedance measurement, which can detect nonacid reflux or weakly acid reflux. However, the clinical significance of this measurement is unclear, as multiple studies have found total acid exposure time to be a better predictor of response to therapy than weakly acid or nonacid reflux.¹²

Wireless pH probe. This method uses a disposable, catheter-free, capsule device to measure esophageal pH. The capsule, about the size of a gel capsule or pencil eraser, is attached to the patient’s esophageal lining, usually during upper endoscopy. The capsule records pH levels in the lower esophagus for 48 to 96 hours and transmits the data wirelessly to a receiver the patient wears. The patient pushes buttons on the receiver to record symptom-specific data when experiencing heartburn, chest pain, regurgitation, or cough. The capsule detaches from the esophagus spontaneously, generally within 7 days, and is passed out of the body through a bowel movement.

Diagnosing functional heartburn

CASE CONTINUED: NORMAL RESULTS ON TESTING

Based on these results, her condition is diagnosed as functional heartburn, consistent with the Rome IV criteria.⁵

Patient education is key

Patient education about the pathogenesis, natural history, and treatment options is the most important aspect of treating any functional gastrointestinal disorder. This includes the “brain-gut connection” and potential mechanisms of dysregulation. Patient education along with assessment of symptoms should be part of every visit, especially before discussing treatment options.

Patients whose condition is diagnosed as functional heartburn need reassurance that the condition is benign and, in particular, that the risk of progression to esophageal adenocarcinoma is minimal in the absence of Barrett esophagus.¹³ Also important to point out is that the disorder may spontaneously resolve: resolution rates of up to 40% have been reported for other functional gastrointestinal disorders.¹⁴

Antisecretory medications may work for some

A PPI or H₂-receptor antagonist is the most common first-line treatment for heartburn symptoms. Although most patients with functional heartburn experience no improvement in symptoms with an antisecretory agent, a small number report some relief, which suggests that acid-suppression therapy may have an indirect impact on pain modulation in the esophagus.¹⁵ In patients who report symptom relief with an antisecretory agent, we suggest continuing the medication tapered to the lowest effective dose, with repeated reassurance that the medication can be discontinued safely at any time.

Antireflux surgery should be avoided

Antireflux surgery should be avoided in patients with normal pH testing and no objective finding of reflux, as this is associated with worse subjective outcomes than in patients with abnormal pH test results.¹⁶

Neuromodulators

It is important to discuss with patients the concept of neuromodulation, including the fact that antidepressants are often used because of their effects on serotonin and norepinephrine, which decrease visceral hypersensitivity.

The selective serotonin reuptake inhibitor citalopram has been shown to reduce esophageal hypersensitivity,¹⁷ and a tricyclic antidepressant has been shown to improve quality of life.¹⁸ These results have led experts to recommend a trial of a low dose of either type of medication.¹⁹ The dose of tricyclic antidepressant often needs to be increased sequentially every 2 to 4 weeks.

Interestingly, melatonin 6 mg at bedtime has also shown efficacy for functional heartburn, potentially due to its antinociceptive properties.²⁰

Alternative and complementary therapies

Many esophageal centers use cognitive behavioral therapy and hypnotherapy as first-line treatment for functional esophageal disorders. Here again, it is important for the patient to understand the rationale of therapy for functional gastrointestinal disorders, given the stigma in the general population regarding psychotherapy.

Cognitive behavioral therapy has been used for functional gastrointestinal disorders for many years, as it has been shown to modulate visceral perception.²¹ Although published studies are limited, research regarding other functional esophageal disorders suggests that patients who commit to long-term behavioral therapy have had a significant improvement in symptoms.²²

The goal of esophageal-directed behavioral therapy is to promote focused relaxation using deep breathing techniques, which can help patients manage esophageal hypervigilance, especially if symptoms continue despite neuromodulator therapy. Specifically, hypnotherapy has been shown to modulate functional chest pain through the visceral sensory pathway and also to suppress gastric acid secretion.^21,23 A study of a 7-week hypnotherapy program reported significant benefits in heartburn relief and improved quality of life in patients with functional heartburn.²⁴ The data support the use of behavioral therapies as first-line therapy or as adjunctive therapy for patients already taking a neuromodulator.

CASE FOLLOW-UP: IMPROVEMENT WITH TREATMENT

During a follow-up visit, the patient is given several printed resources, including the Rome Foundation article on functional heartburn.⁵ We again emphasize the benign nature of functional heartburn, noting the minimal risk of progression to esophageal adenocarcinoma, as she had no evidence of Barrett esophagus on endoscopy. And we discuss the natural course of functional heartburn, including the spontaneous resolution rate of about 40%.

For treatment, we present her the rationale for using neuromodulators and reassure her that these medications are for treatment of visceral hypersensitivity, not for anxiety or depression. After the discussion, the patient opts to start amitriptyline therapy at 10 mg every night at bedtime, increasing the dose by 10 mg every 2 weeks until symptoms improve, up to 75–100 mg every day.

After 3 months, the patient reports a 90% improvement in symptoms while on amitriptyline 30 mg every night. She is also able to taper her antisecretory medications once symptoms are controlled. We plan to continue amitriptyline at the current dose for 6 to 12 months, then discuss a slow taper to see if her symptoms spontaneously resolve.

A 44-year-old woman presents with an 8-year history of intermittent heartburn, and in the past year she has been experiencing her symptoms daily. She says the heartburn is constant and is worse immediately after eating spicy or acidic foods. She says she has had no dysphagia, weight loss, or vomiting. Her symptoms have persisted despite taking a histamine (H)₂-receptor antagonist twice daily plus a proton pump inhibitor (PPI) before breakfast and dinner for more than 3 months.

She has undergone upper endoscopy 3 times in the past 8 years. Each time, the esophagus was normal with a regular Z-line and normal biopsy results from the proximal and distal esophagus.

The patient believes she has severe gastroesophageal reflux disease (GERD) and asks if she is a candidate for fundoplication surgery.

HEARTBURN IS A SYMPTOM; GERD IS A CONDITION

A distinction should be made between heartburn—the symptom of persistent retrosternal burning and discomfort—and gastroesophageal reflux disease—the condition in which reflux of stomach contents causes troublesome symptoms or complications.¹ While many clinicians initially diagnose patients who have heartburn as having GERD, there are many other potential causes of their symptoms.

For patients with persistent heartburn, an empiric trial of a once-daily PPI is usually effective, but one-third of patients continue to have heartburn.^2,3 The most common cause of this PPI-refractory heartburn is functional heartburn, a functional or hypersensitivity disorder of the esophagus.⁴

PATHOPHYSIOLOGY IS POORLY UNDERSTOOD

DIAGNOSTIC EVALUATION

Clinicians have several tests available for diagnosing these conditions.

Upper endoscopy

Upper endoscopy is recommended for patients with heartburn that does not respond to a 3-month trial of a PPI.⁹ Endoscopy is also indicated in any patient who has any of the following “alarm symptoms” that could be due to malignancy or peptic ulcer:

• Dysphagia
• Odynophagia
• Vomiting
• Unexplained weight loss or anemia
• Signs of gastrointestinal bleeding
• Anorexia
• New onset of dyspepsia in a patient over age 60.

During upper endoscopy, the esophagus is evaluated for reflux esophagitis, Barrett esophagus, and other inflammatory disorders such as infectious esophagitis. But even if the esophageal mucosa appears normal, the proximal and distal esophagus should be biopsied to rule out an inflammatory disorder such as eosinophilic or lymphocytic esophagitis.

If endoscopic and esophageal biopsy results are inconclusive, a workup for an esophageal motility disorder is the next step. Dysphagia is the most common symptom of these disorders, although the initial presenting symptom may be heartburn or regurgitation that persists despite PPI therapy.

Manometry is used to test for motility disorders such as achalasia and esophageal spasm.¹⁰ After applying a local anesthetic inside the nares, the clinician inserts a flexible catheter (about 4 mm in diameter) with 36 pressure sensors spaced at 1-cm intervals into the nares and passes it through the esophagus and lower esophageal sphincter. The patient then swallows liquid, and the sensors relay the esophageal response, creating a topographic plot that shows esophageal peristalsis and lower esophageal sphincter relaxation.

Achalasia is identified by incomplete lower esophageal sphincter relaxation combined with 100% failed peristalsis in the body of the esophagus. Esophageal spasms are identified by a shortened distal latency, which corresponds to premature contraction of the esophagus during peristalsis.¹¹

Esophageal pH testing

Measuring esophageal pH levels is an important step to quantify gastroesophageal reflux and determine if symptoms occur during reflux events. According to the updated Porto GERD consensus group recommendations,¹² a pH test is positive if the acid exposure time is greater than 6% of the testing period. Testing the pH differentiates between GERD (abnormal acid exposure), reflux hypersensitivity (normal acid exposure, strong correlation between symptoms and reflux events), and functional heartburn (normal acid exposure, negative correlation between reflux events and symptoms).⁵ For this test, a pH probe is placed in the esophagus transnasally or endoscopically. The probe records esophageal pH levels for 24 to 96 hours in an outpatient setting. Antisecretory therapy needs to be withheld for 7 to 10 days before the test.

Transnasal pH probe. For this approach, a thin catheter is inserted through the nares and advanced until the tip is 5 cm proximal to the lower esophageal sphincter. (The placement is guided by the results of esophageal manometry, which is done immediately before pH catheter placement.) The tube is secured with clear tape on the side of the patient’s face, and the end is connected to a portable recorder that compiles the data. The patient pushes a button on the recorder when experiencing heartburn symptoms. (A nurse instructs the patient on proper procedure.) After 24 hours, the patient either removes the catheter or has the clinic remove it. The pH and symptom data are downloaded and analyzed.

Transnasal pH testing can be combined with impedance measurement, which can detect nonacid reflux or weakly acid reflux. However, the clinical significance of this measurement is unclear, as multiple studies have found total acid exposure time to be a better predictor of response to therapy than weakly acid or nonacid reflux.¹²

Wireless pH probe. This method uses a disposable, catheter-free, capsule device to measure esophageal pH. The capsule, about the size of a gel capsule or pencil eraser, is attached to the patient’s esophageal lining, usually during upper endoscopy. The capsule records pH levels in the lower esophagus for 48 to 96 hours and transmits the data wirelessly to a receiver the patient wears. The patient pushes buttons on the receiver to record symptom-specific data when experiencing heartburn, chest pain, regurgitation, or cough. The capsule detaches from the esophagus spontaneously, generally within 7 days, and is passed out of the body through a bowel movement.

Diagnosing functional heartburn

CASE CONTINUED: NORMAL RESULTS ON TESTING

Based on these results, her condition is diagnosed as functional heartburn, consistent with the Rome IV criteria.⁵

Patient education is key

Patient education about the pathogenesis, natural history, and treatment options is the most important aspect of treating any functional gastrointestinal disorder. This includes the “brain-gut connection” and potential mechanisms of dysregulation. Patient education along with assessment of symptoms should be part of every visit, especially before discussing treatment options.

Patients whose condition is diagnosed as functional heartburn need reassurance that the condition is benign and, in particular, that the risk of progression to esophageal adenocarcinoma is minimal in the absence of Barrett esophagus.¹³ Also important to point out is that the disorder may spontaneously resolve: resolution rates of up to 40% have been reported for other functional gastrointestinal disorders.¹⁴

Antisecretory medications may work for some

A PPI or H₂-receptor antagonist is the most common first-line treatment for heartburn symptoms. Although most patients with functional heartburn experience no improvement in symptoms with an antisecretory agent, a small number report some relief, which suggests that acid-suppression therapy may have an indirect impact on pain modulation in the esophagus.¹⁵ In patients who report symptom relief with an antisecretory agent, we suggest continuing the medication tapered to the lowest effective dose, with repeated reassurance that the medication can be discontinued safely at any time.

Antireflux surgery should be avoided

Antireflux surgery should be avoided in patients with normal pH testing and no objective finding of reflux, as this is associated with worse subjective outcomes than in patients with abnormal pH test results.¹⁶

Neuromodulators

It is important to discuss with patients the concept of neuromodulation, including the fact that antidepressants are often used because of their effects on serotonin and norepinephrine, which decrease visceral hypersensitivity.

The selective serotonin reuptake inhibitor citalopram has been shown to reduce esophageal hypersensitivity,¹⁷ and a tricyclic antidepressant has been shown to improve quality of life.¹⁸ These results have led experts to recommend a trial of a low dose of either type of medication.¹⁹ The dose of tricyclic antidepressant often needs to be increased sequentially every 2 to 4 weeks.

Interestingly, melatonin 6 mg at bedtime has also shown efficacy for functional heartburn, potentially due to its antinociceptive properties.²⁰

Alternative and complementary therapies

Many esophageal centers use cognitive behavioral therapy and hypnotherapy as first-line treatment for functional esophageal disorders. Here again, it is important for the patient to understand the rationale of therapy for functional gastrointestinal disorders, given the stigma in the general population regarding psychotherapy.

Cognitive behavioral therapy has been used for functional gastrointestinal disorders for many years, as it has been shown to modulate visceral perception.²¹ Although published studies are limited, research regarding other functional esophageal disorders suggests that patients who commit to long-term behavioral therapy have had a significant improvement in symptoms.²²

The goal of esophageal-directed behavioral therapy is to promote focused relaxation using deep breathing techniques, which can help patients manage esophageal hypervigilance, especially if symptoms continue despite neuromodulator therapy. Specifically, hypnotherapy has been shown to modulate functional chest pain through the visceral sensory pathway and also to suppress gastric acid secretion.^21,23 A study of a 7-week hypnotherapy program reported significant benefits in heartburn relief and improved quality of life in patients with functional heartburn.²⁴ The data support the use of behavioral therapies as first-line therapy or as adjunctive therapy for patients already taking a neuromodulator.

CASE FOLLOW-UP: IMPROVEMENT WITH TREATMENT

During a follow-up visit, the patient is given several printed resources, including the Rome Foundation article on functional heartburn.⁵ We again emphasize the benign nature of functional heartburn, noting the minimal risk of progression to esophageal adenocarcinoma, as she had no evidence of Barrett esophagus on endoscopy. And we discuss the natural course of functional heartburn, including the spontaneous resolution rate of about 40%.

For treatment, we present her the rationale for using neuromodulators and reassure her that these medications are for treatment of visceral hypersensitivity, not for anxiety or depression. After the discussion, the patient opts to start amitriptyline therapy at 10 mg every night at bedtime, increasing the dose by 10 mg every 2 weeks until symptoms improve, up to 75–100 mg every day.

After 3 months, the patient reports a 90% improvement in symptoms while on amitriptyline 30 mg every night. She is also able to taper her antisecretory medications once symptoms are controlled. We plan to continue amitriptyline at the current dose for 6 to 12 months, then discuss a slow taper to see if her symptoms spontaneously resolve.

Most tricyclic antidepressants (TCAs) have US Food and Drug Administration approval for treatment of depression and anxiety disorders, but they are also a viable off-label option that should be considered by clinicians in specialties beyond psychiatry, especially for treating pain syndromes. Given the ongoing epidemic of opioid use disorder, increasing attention has been drawn to alternative strategies for chronic pain management, renewing an interest in the use of TCAs.

This review summarizes the pharmacologic properties of TCAs, their potential indications in conditions other than depression, and safety considerations.

BRIEF HISTORY OF TRICYCLICS

TCAs were originally designed in the 1950s and marketed later for treating depression. Due to their adverse effects and lethality in overdose quantities, over time they have been largely replaced by selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) in depression management. However, TCAs have been applied to conditions other than depression with varying degrees of efficacy and safety.

TCA PHARMACOLOGY

TCAs are absorbed in the small intestine and undergo first-pass metabolism in the liver. They bind extensively to proteins, leading to interactions with other protein-bound drugs. They are widely distributed throughout the systemic circulation because they are highly lipophilic, resulting in systemic effects including central nervous system manifestations.

Peak plasma concentration is at about 2 to 6 hours, and elimination half-life is around 24 hours for most agents, providing a long duration of action. Clearance depends on cytochrome P450 oxidative enzymes.¹

MECHANISMS OF ACTION

TCAs inhibit reuptake of norepinephrine and serotonin, resulting in accumulation of these neurotransmitters in the presynaptic cleft. They also block postsynaptic histamine, alpha-adrenergic, and muscarinic-acetylcholine receptors, causing a variety of adverse effects, including dry mouth, confusion, cognitive impairment, hypotension, orthostasis, blurred vision, urinary retention, drowsiness, and sedation.¹

Research suggests that TCAs relieve pain centrally through a descending pathway that inhibits transmission of pain signals in the spinal cord, as well as peripherally through complex anti-neuroimmune actions.² Norepinephrine appears to play a more important role in this process than serotonin, although both are deemed necessary for the “dual action” often cited in pain management,¹ which is also the rationale for widespread use of SNRIs to control pain.

Table 1 compares neurotransmitter reuptake mechanisms, adverse effect profiles, and typical dosages for depression for commonly prescribed TCAs.

POTENTIAL USES

Headache and migraine

TCAs have been shown to be effective for managing and preventing chronic headache syndromes.^3,4 Amitriptyline has been the most studied of the TCAs for both chronic daily and episodic migraine headache, showing the most efficacy among diverse drug classes (angiotensin II receptor blockers, anticonvulsants, beta-blockers, SSRIs) compared with placebo. However, in head-to-head trials, amitriptyline was no more effective than SSRIs, venlafaxine, topiramate, or propranolol.⁴ Jackson et al⁴ suggested that prophylactic medication choices should be tailored to patient characteristics and expected adverse effects, and specifically recommended that TCAs—particularly amitriptyline—be reserved for patients who have both migraine and depression.

Neuropathic pain

Neuropathic pain is defined as pain secondary to a lesion or disease of the somatosensory nervous system⁵ and is the pathomechanistic component of a number of conditions, including postherpetic neuralgia,⁶ diabetic and nondiabetic painful polyneuropathy,⁷ posttraumatic or postsurgical neuropathic pain⁸ (including plexus avulsion and complex regional pain syndrome⁹), central poststroke pain,¹⁰ spinal cord injury pain,¹¹ and multiple sclerosis-associated pain.¹²

As a group, TCAs appear to have a role as first-line agents for managing these varied neuropathic pain syndromes. In a recent meta-analysis,¹³ 16 (89%) of 18 placebo-controlled trials of TCAs (mainly amitriptyline at 25–150 mg/day) for these pain conditions were positive, with a combined number needed to treat of 3.6, suggesting a role for TCAs in these conditions. Of note, the TCAs desipramine¹⁴ and nortriptyline¹⁵ have demonstrated little evidence of efficacy in neuropathic pain syndromes.

Chronic low back pain

Chronic low back pain is a leading cause of loss of work, excessive healthcare expenditure, and disability in the United States. It can be due to numerous spinal conditions, including degenerative disk disease, spinal stenosis, lumbar spondylosis, and spinal arthropathy.

TCAs have been used to treat chronic low back pain for decades and have been repeatedly shown to be more effective than placebo in reducing pain severity.^16,17 A double-blind controlled trial¹⁸ from 1999 compared the effects of the TCA maprotiline (up to 150 mg daily), the SSRI paroxetine (up to 30 mg daily), and placebo and found a statistically significant reduction in back pain with maprotiline compared with paroxetine and placebo. However, a 2008 meta-analysis suggested little evidence that TCAs were superior to placebo.¹⁹

Evidence of TCA efficacy for back pain was reported in 2018 with a well-designed 6-month double-blind randomized controlled trial²⁰ comparing low-dose amitriptyline (25 mg) with an active comparator (benztropine 1 mg). The authors reported that amitriptyline was effective in reducing pain and pain-related disability without incurring serious adverse effects. They suggested continued use of TCAs for chronic low back pain if complicated with pain-related disability, insomnia, depression, or other comorbidity, although they called for further large-scale studies. They also cautioned that patients started the trial with symptoms similar to the adverse effects of TCAs themselves; this has implications for monitoring of symptoms as well as TCA adverse effects while using these drugs.

Fibromyalgia is a common, frustrating, noninflammatory pain syndrome characterized by diffuse hyperalgesia and multiple comorbidities.²¹ Although sleep hygiene, exercise, cognitive-behavioral therapy, some gabapentinoids (pregabalin), and a combination of these therapies have demonstrated efficacy, TCAs also offer robust benefits.

A meta-analysis of 9 placebo-controlled TCA trials showed large effect sizes for pain reduction, fatigue reduction, improved sleep quality, and reduced stiffness and tenderness, with the most significant of these improvements being for sleep.²² A separate meta-analysis calculated that the number needed to treat with amitriptyline for a positive outcome is 4.9.²³ Recent systematic reviews have supported these findings, listing TCAs as second-line agents after pregabalin, duloxetine, and milnacipran.²⁴

Of note, TCA monotherapy rarely produces a complete response in patients with moderate to severe fibromyalgia, chronic widespread pain, or significant comorbidities (depression, anxiety). Supplementation with cognitive-behavioral therapy, physical therapy, functional restoration, and other modalities is strongly recommended.

Abdominal and gastrointestinal pain

TCAs have been applied to a number of gastrointestinal syndromes with or without pain. Patients with irritable bowel syndrome have long been known to benefit from TCAs; the number needed to treat for symptomatic benefit over placebo is 3.5.^25,26

Although there is no substantial evidence that TCAs are useful in reducing active inflammation in inflammatory bowel disease, a study involving 81 patients found that residual noninflammatory gastrointestinal symptoms (such as diarrhea and pain) responded to TCAs, including nortriptyline and amitriptyline, with greater benefit for ulcerative colitis than for Crohn disease.²⁷

TCAs have also shown prophylactic benefit in cyclic vomiting syndrome, with a clinical response in over 75% of patients in controlled cohort studies.²⁸

The efficacy of TCAs in other abdominal or gastrointestinal syndromes is unclear or modest at best.²⁹ However, few alternative treatments exist for these conditions. Amitriptyline may help symptoms of functional dyspepsia,³⁰ but nortriptyline has proven ineffective in gastroparesis.³¹ Nonetheless, some authors²⁹ suggest considering TCAs on an individualized basis, with proper monitoring, in many if not most functional gastrointestinal disorders, especially when paired with behavioral therapies.

Pelvic and urogynecologic symptoms

Chronic pelvic pain affects up to 24% of women³² and 5% to 10% of men.³³ TCAs have shown efficacy in treating chronic pelvic pain with or without comorbid depression.³⁴ Amitriptyline and to a lesser extent nortriptyline are the TCAs most often prescribed. Pain relief appears to be independent of antidepressant effects and may be achieved at low doses; initial dosing ranges from 10 to 25 mg at bedtime, which may be increased to 100 mg as tolerated.³⁴

Based on a randomized, double-blind trial,³⁵ amitriptyline was recommended as a treatment option for interstitial cystitis or bladder pain, with the greatest symptom improvement in patients tolerating a daily dose of 50 mg.

Another study³⁶ randomized 56 women with chronic pelvic pain to amitriptyline or  gabapentin, or a combination of the drugs for 24 months. Although each regimen resulted in significant reduction in pain, fewer adverse effects occurred with gabapentin than amitriptyline. Poor compliance and early discontinuation of amitriptyline were common due to anticholinergic effects.

In small uncontrolled studies,³⁷ about half of women with chronic pelvic pain became pain-free after 8 weeks of treatment with nortriptyline and imipramine.

Randomized controlled studies are needed to confirm potential benefits of TCAs in chronic urologic and pelvic pain.

Insomnia

Insomnia affects 23% to 56% of people in the United States, Europe, and Asia³⁸ and is the reason for more than 5.5 million primary care visits annually.³⁹ TCAs (especially doxepin, maprotiline, and amitriptyline⁴⁰) have been shown to be an effective treatment, with an 82% increase in somnolence compared with placebo, as well as measurably improved total sleep time, enhanced sleep efficiency, reduced latency to persistent sleep, and decreased wake times after sleep onset.³⁸

Dosing should be kept at a minimum to minimize harsh anticholinergic effects and avoid daytime sedation. Patients should be advised to take new doses or dose escalations earlier in the night to ensure less hangover sedation the next morning.

For patients with insomnia and comorbid depression, the American Academy of Sleep Medicine suggests the addition of a low dose (eg, 10–25 mg) of a TCA at nighttime to complement preexisting, full-dose, non-TCA antidepressants, while monitoring for serotonin syndrome and other potential but exceedingly rare drug-drug interactions.⁴¹

Psychiatric indications other than depression

Beyond the known benefits in major depressive disorder, TCAs have been shown to be effective for obsessive-compulsive disorder, panic disorder, posttraumatic stress disorder, bulimia nervosa, and childhood enuresis.⁴² Given the shortage of mental health clinicians and the high prevalence of these conditions, nonpsychiatrist physicians should be familiar with the therapeutic potential of TCAs for these indications.

ADVERSE EFFECTS

Adverse effects vary among TCAs. Common ones include blurred vision, dry mouth, constipation, urinary retention, hypotension, tachycardia, tremor, weight gain, and sexual dysfunction.⁴³ Tertiary amines are generally more sedating than secondary amines and cause more anticholinergic effects (Table 1).

Despite widespread perceptions that TCAs are less tolerable than newer antidepressants, studies repeatedly suggest that they have an adverse-effect burden similar to that of SSRIs and SNRIs, although SSRIs have a greater tendency to produce nausea, whereas TCAs are more likely to cause constipation.⁴⁴

Discontinuation syndrome

Abrupt discontinuation or unintentionally missed doses of TCAs have been associated with a discontinuation syndrome in about 40% of users.⁴⁵ Patients should be warned about this possibility and the syndrome’s potential effects: dizziness, insomnia, headaches, nausea, vomiting, flulike achiness, and restlessness. Rebound depression, anxiety, panic, or other psychiatric symptoms may also occur. Symptoms generally present within 2 to 5 days after dose discontinuation and last 7 to 14 days.⁴⁵

However, all TCAs have a long half-life, allowing for sufficient coverage with once-daily dosing and thus carry a lower risk of discontinuation syndrome than many other antidepressants (78% with venlafaxine; 55% with paroxetine).⁴⁵

To discontinue therapy safely, the dosage should be reduced gradually. As is pharmacologically expected, the greatest likelihood of discontinuation syndrome is associated with longer duration of continuous treatment.

CONTRAINDICATIONS

Cardiac conduction abnormalities

TCAs should not be prescribed to patients who have right bundle branch block, a severe electrolyte disturbance, or other cardiac conduction deficit or arrhythmia that can prolong the QTc interval and elevate the risk of lethal arrhythmia.^46,47 Cardiac effects from TCAs are largely dose-dependent. Nevertheless, a baseline electrocardiogram can be obtained to assess cardiac risk, and dose escalation can proceed if results are normal (eg, appropriate conduction intervals, QTc ≤ 450 ms).

Advanced age

For elderly patients, TCAs should be prescribed with caution and sometimes not at all,⁴⁸ because anticholinergic effects may worsen preexisting urinary retention (including benign prostatic hyperplasia), narrow-angle glaucoma, imbalance and gait issues, and cognitive impairment and dementia. Dehydration and orthostatic hypotension are contraindications for TCAs, as they may precipitate falls or hypotensive shock.

Epilepsy

TCAs should also be used with caution in patients with epilepsy, as they lower the seizure threshold.

Concomitant monoamine oxidase inhibitor treatment

Giving TCAs together with monoamine oxidase inhibitor antidepressants should be avoided, given the risk of hypertensive crisis.

Suicide risk

TCAs are dangerous and potentially lethal in overdose and so should not be prescribed to suicidal or otherwise impulsive patients.

Pregnancy

TCAs are in pregnancy risk category C (animal studies show adverse effects on fetus; no adequate or well-controlled studies in humans; potential benefits may warrant use despite risks). Using TCAs during pregnancy has very rarely led to neonatal withdrawal such as irritability, jitteriness, and convulsions, as well as fetal QTc interval prolongation.⁴⁹

The American College of Obstetricians and Gynecologists recommends that therapy for depression during pregnancy be individualized, incorporating the expertise of the patient’s mental health clinician, obstetrician, primary healthcare provider, and pediatrician. In general, they recommend that TCAs should be avoided if possible and that alternatives such as SSRIs or SNRIs should be considered.⁵⁰

TCAs are excreted in breast milk, but they have not been detected in the serum of nursing infants, and no adverse events have been reported.

OVERDOSE IS HIGHLY DANGEROUS

Severe morbidity and death are associated with TCA overdose, characterized by  convulsions, cardiac arrest, and coma (the “3 Cs”). These dangers occur at much higher rates with TCAs than with other antidepressants.⁴³ Signs and symptoms of toxicity develop rapidly, usually within the first hour of overdose. Manifestations of overdose include prolonged QTc, cardiac arrhythmias, tachycardia, hypertension, severe hypotension, agitation, seizures, central nervous system depression, hallucinations, seizures, and coma.

Overdose management includes activated charcoal, seizure control, cardioversion, hydration, electrolyte stabilization, and other intensive care.

OFF-LABEL TCA MANAGEMENT

Dosing recommendations for off-label use of TCAs vary based on the condition, the medication, and the suggestions of individual authors and researchers. In general, dosing ranges for pain and other nondepression indications may be lower than for severe depression (Table 2).¹

As with any pharmacologic titration, monitoring for rate-limiting adverse effects is recommended. We suggest caution, tailoring the approach to the patient, and routinely assessing for adverse effects and other safety considerations.

In addition, we strongly recommend supplementing TCA therapy with nonpharmacologic strategies such as lifestyle changes, dietary modifications, exercise, physical therapy, and mental health optimization.

Most tricyclic antidepressants (TCAs) have US Food and Drug Administration approval for treatment of depression and anxiety disorders, but they are also a viable off-label option that should be considered by clinicians in specialties beyond psychiatry, especially for treating pain syndromes. Given the ongoing epidemic of opioid use disorder, increasing attention has been drawn to alternative strategies for chronic pain management, renewing an interest in the use of TCAs.

This review summarizes the pharmacologic properties of TCAs, their potential indications in conditions other than depression, and safety considerations.

BRIEF HISTORY OF TRICYCLICS

TCAs were originally designed in the 1950s and marketed later for treating depression. Due to their adverse effects and lethality in overdose quantities, over time they have been largely replaced by selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) in depression management. However, TCAs have been applied to conditions other than depression with varying degrees of efficacy and safety.

TCA PHARMACOLOGY

TCAs are absorbed in the small intestine and undergo first-pass metabolism in the liver. They bind extensively to proteins, leading to interactions with other protein-bound drugs. They are widely distributed throughout the systemic circulation because they are highly lipophilic, resulting in systemic effects including central nervous system manifestations.

Peak plasma concentration is at about 2 to 6 hours, and elimination half-life is around 24 hours for most agents, providing a long duration of action. Clearance depends on cytochrome P450 oxidative enzymes.¹

MECHANISMS OF ACTION

TCAs inhibit reuptake of norepinephrine and serotonin, resulting in accumulation of these neurotransmitters in the presynaptic cleft. They also block postsynaptic histamine, alpha-adrenergic, and muscarinic-acetylcholine receptors, causing a variety of adverse effects, including dry mouth, confusion, cognitive impairment, hypotension, orthostasis, blurred vision, urinary retention, drowsiness, and sedation.¹

Research suggests that TCAs relieve pain centrally through a descending pathway that inhibits transmission of pain signals in the spinal cord, as well as peripherally through complex anti-neuroimmune actions.² Norepinephrine appears to play a more important role in this process than serotonin, although both are deemed necessary for the “dual action” often cited in pain management,¹ which is also the rationale for widespread use of SNRIs to control pain.

Table 1 compares neurotransmitter reuptake mechanisms, adverse effect profiles, and typical dosages for depression for commonly prescribed TCAs.

POTENTIAL USES

Headache and migraine

TCAs have been shown to be effective for managing and preventing chronic headache syndromes.^3,4 Amitriptyline has been the most studied of the TCAs for both chronic daily and episodic migraine headache, showing the most efficacy among diverse drug classes (angiotensin II receptor blockers, anticonvulsants, beta-blockers, SSRIs) compared with placebo. However, in head-to-head trials, amitriptyline was no more effective than SSRIs, venlafaxine, topiramate, or propranolol.⁴ Jackson et al⁴ suggested that prophylactic medication choices should be tailored to patient characteristics and expected adverse effects, and specifically recommended that TCAs—particularly amitriptyline—be reserved for patients who have both migraine and depression.

Neuropathic pain

Neuropathic pain is defined as pain secondary to a lesion or disease of the somatosensory nervous system⁵ and is the pathomechanistic component of a number of conditions, including postherpetic neuralgia,⁶ diabetic and nondiabetic painful polyneuropathy,⁷ posttraumatic or postsurgical neuropathic pain⁸ (including plexus avulsion and complex regional pain syndrome⁹), central poststroke pain,¹⁰ spinal cord injury pain,¹¹ and multiple sclerosis-associated pain.¹²

As a group, TCAs appear to have a role as first-line agents for managing these varied neuropathic pain syndromes. In a recent meta-analysis,¹³ 16 (89%) of 18 placebo-controlled trials of TCAs (mainly amitriptyline at 25–150 mg/day) for these pain conditions were positive, with a combined number needed to treat of 3.6, suggesting a role for TCAs in these conditions. Of note, the TCAs desipramine¹⁴ and nortriptyline¹⁵ have demonstrated little evidence of efficacy in neuropathic pain syndromes.

Chronic low back pain

Chronic low back pain is a leading cause of loss of work, excessive healthcare expenditure, and disability in the United States. It can be due to numerous spinal conditions, including degenerative disk disease, spinal stenosis, lumbar spondylosis, and spinal arthropathy.

TCAs have been used to treat chronic low back pain for decades and have been repeatedly shown to be more effective than placebo in reducing pain severity.^16,17 A double-blind controlled trial¹⁸ from 1999 compared the effects of the TCA maprotiline (up to 150 mg daily), the SSRI paroxetine (up to 30 mg daily), and placebo and found a statistically significant reduction in back pain with maprotiline compared with paroxetine and placebo. However, a 2008 meta-analysis suggested little evidence that TCAs were superior to placebo.¹⁹

Evidence of TCA efficacy for back pain was reported in 2018 with a well-designed 6-month double-blind randomized controlled trial²⁰ comparing low-dose amitriptyline (25 mg) with an active comparator (benztropine 1 mg). The authors reported that amitriptyline was effective in reducing pain and pain-related disability without incurring serious adverse effects. They suggested continued use of TCAs for chronic low back pain if complicated with pain-related disability, insomnia, depression, or other comorbidity, although they called for further large-scale studies. They also cautioned that patients started the trial with symptoms similar to the adverse effects of TCAs themselves; this has implications for monitoring of symptoms as well as TCA adverse effects while using these drugs.

Fibromyalgia is a common, frustrating, noninflammatory pain syndrome characterized by diffuse hyperalgesia and multiple comorbidities.²¹ Although sleep hygiene, exercise, cognitive-behavioral therapy, some gabapentinoids (pregabalin), and a combination of these therapies have demonstrated efficacy, TCAs also offer robust benefits.

A meta-analysis of 9 placebo-controlled TCA trials showed large effect sizes for pain reduction, fatigue reduction, improved sleep quality, and reduced stiffness and tenderness, with the most significant of these improvements being for sleep.²² A separate meta-analysis calculated that the number needed to treat with amitriptyline for a positive outcome is 4.9.²³ Recent systematic reviews have supported these findings, listing TCAs as second-line agents after pregabalin, duloxetine, and milnacipran.²⁴

Of note, TCA monotherapy rarely produces a complete response in patients with moderate to severe fibromyalgia, chronic widespread pain, or significant comorbidities (depression, anxiety). Supplementation with cognitive-behavioral therapy, physical therapy, functional restoration, and other modalities is strongly recommended.

Abdominal and gastrointestinal pain

TCAs have been applied to a number of gastrointestinal syndromes with or without pain. Patients with irritable bowel syndrome have long been known to benefit from TCAs; the number needed to treat for symptomatic benefit over placebo is 3.5.^25,26

Although there is no substantial evidence that TCAs are useful in reducing active inflammation in inflammatory bowel disease, a study involving 81 patients found that residual noninflammatory gastrointestinal symptoms (such as diarrhea and pain) responded to TCAs, including nortriptyline and amitriptyline, with greater benefit for ulcerative colitis than for Crohn disease.²⁷

TCAs have also shown prophylactic benefit in cyclic vomiting syndrome, with a clinical response in over 75% of patients in controlled cohort studies.²⁸

The efficacy of TCAs in other abdominal or gastrointestinal syndromes is unclear or modest at best.²⁹ However, few alternative treatments exist for these conditions. Amitriptyline may help symptoms of functional dyspepsia,³⁰ but nortriptyline has proven ineffective in gastroparesis.³¹ Nonetheless, some authors²⁹ suggest considering TCAs on an individualized basis, with proper monitoring, in many if not most functional gastrointestinal disorders, especially when paired with behavioral therapies.

Pelvic and urogynecologic symptoms

Chronic pelvic pain affects up to 24% of women³² and 5% to 10% of men.³³ TCAs have shown efficacy in treating chronic pelvic pain with or without comorbid depression.³⁴ Amitriptyline and to a lesser extent nortriptyline are the TCAs most often prescribed. Pain relief appears to be independent of antidepressant effects and may be achieved at low doses; initial dosing ranges from 10 to 25 mg at bedtime, which may be increased to 100 mg as tolerated.³⁴

Based on a randomized, double-blind trial,³⁵ amitriptyline was recommended as a treatment option for interstitial cystitis or bladder pain, with the greatest symptom improvement in patients tolerating a daily dose of 50 mg.

Another study³⁶ randomized 56 women with chronic pelvic pain to amitriptyline or  gabapentin, or a combination of the drugs for 24 months. Although each regimen resulted in significant reduction in pain, fewer adverse effects occurred with gabapentin than amitriptyline. Poor compliance and early discontinuation of amitriptyline were common due to anticholinergic effects.

In small uncontrolled studies,³⁷ about half of women with chronic pelvic pain became pain-free after 8 weeks of treatment with nortriptyline and imipramine.

Randomized controlled studies are needed to confirm potential benefits of TCAs in chronic urologic and pelvic pain.

Insomnia

Insomnia affects 23% to 56% of people in the United States, Europe, and Asia³⁸ and is the reason for more than 5.5 million primary care visits annually.³⁹ TCAs (especially doxepin, maprotiline, and amitriptyline⁴⁰) have been shown to be an effective treatment, with an 82% increase in somnolence compared with placebo, as well as measurably improved total sleep time, enhanced sleep efficiency, reduced latency to persistent sleep, and decreased wake times after sleep onset.³⁸

Dosing should be kept at a minimum to minimize harsh anticholinergic effects and avoid daytime sedation. Patients should be advised to take new doses or dose escalations earlier in the night to ensure less hangover sedation the next morning.

For patients with insomnia and comorbid depression, the American Academy of Sleep Medicine suggests the addition of a low dose (eg, 10–25 mg) of a TCA at nighttime to complement preexisting, full-dose, non-TCA antidepressants, while monitoring for serotonin syndrome and other potential but exceedingly rare drug-drug interactions.⁴¹

Psychiatric indications other than depression

Beyond the known benefits in major depressive disorder, TCAs have been shown to be effective for obsessive-compulsive disorder, panic disorder, posttraumatic stress disorder, bulimia nervosa, and childhood enuresis.⁴² Given the shortage of mental health clinicians and the high prevalence of these conditions, nonpsychiatrist physicians should be familiar with the therapeutic potential of TCAs for these indications.

ADVERSE EFFECTS

Adverse effects vary among TCAs. Common ones include blurred vision, dry mouth, constipation, urinary retention, hypotension, tachycardia, tremor, weight gain, and sexual dysfunction.⁴³ Tertiary amines are generally more sedating than secondary amines and cause more anticholinergic effects (Table 1).

Despite widespread perceptions that TCAs are less tolerable than newer antidepressants, studies repeatedly suggest that they have an adverse-effect burden similar to that of SSRIs and SNRIs, although SSRIs have a greater tendency to produce nausea, whereas TCAs are more likely to cause constipation.⁴⁴

Discontinuation syndrome

Abrupt discontinuation or unintentionally missed doses of TCAs have been associated with a discontinuation syndrome in about 40% of users.⁴⁵ Patients should be warned about this possibility and the syndrome’s potential effects: dizziness, insomnia, headaches, nausea, vomiting, flulike achiness, and restlessness. Rebound depression, anxiety, panic, or other psychiatric symptoms may also occur. Symptoms generally present within 2 to 5 days after dose discontinuation and last 7 to 14 days.⁴⁵

However, all TCAs have a long half-life, allowing for sufficient coverage with once-daily dosing and thus carry a lower risk of discontinuation syndrome than many other antidepressants (78% with venlafaxine; 55% with paroxetine).⁴⁵

To discontinue therapy safely, the dosage should be reduced gradually. As is pharmacologically expected, the greatest likelihood of discontinuation syndrome is associated with longer duration of continuous treatment.

CONTRAINDICATIONS

Cardiac conduction abnormalities

TCAs should not be prescribed to patients who have right bundle branch block, a severe electrolyte disturbance, or other cardiac conduction deficit or arrhythmia that can prolong the QTc interval and elevate the risk of lethal arrhythmia.^46,47 Cardiac effects from TCAs are largely dose-dependent. Nevertheless, a baseline electrocardiogram can be obtained to assess cardiac risk, and dose escalation can proceed if results are normal (eg, appropriate conduction intervals, QTc ≤ 450 ms).

Advanced age

For elderly patients, TCAs should be prescribed with caution and sometimes not at all,⁴⁸ because anticholinergic effects may worsen preexisting urinary retention (including benign prostatic hyperplasia), narrow-angle glaucoma, imbalance and gait issues, and cognitive impairment and dementia. Dehydration and orthostatic hypotension are contraindications for TCAs, as they may precipitate falls or hypotensive shock.

Epilepsy

TCAs should also be used with caution in patients with epilepsy, as they lower the seizure threshold.

Concomitant monoamine oxidase inhibitor treatment

Giving TCAs together with monoamine oxidase inhibitor antidepressants should be avoided, given the risk of hypertensive crisis.

Suicide risk

TCAs are dangerous and potentially lethal in overdose and so should not be prescribed to suicidal or otherwise impulsive patients.

Pregnancy

TCAs are in pregnancy risk category C (animal studies show adverse effects on fetus; no adequate or well-controlled studies in humans; potential benefits may warrant use despite risks). Using TCAs during pregnancy has very rarely led to neonatal withdrawal such as irritability, jitteriness, and convulsions, as well as fetal QTc interval prolongation.⁴⁹

The American College of Obstetricians and Gynecologists recommends that therapy for depression during pregnancy be individualized, incorporating the expertise of the patient’s mental health clinician, obstetrician, primary healthcare provider, and pediatrician. In general, they recommend that TCAs should be avoided if possible and that alternatives such as SSRIs or SNRIs should be considered.⁵⁰

TCAs are excreted in breast milk, but they have not been detected in the serum of nursing infants, and no adverse events have been reported.

OVERDOSE IS HIGHLY DANGEROUS

Severe morbidity and death are associated with TCA overdose, characterized by  convulsions, cardiac arrest, and coma (the “3 Cs”). These dangers occur at much higher rates with TCAs than with other antidepressants.⁴³ Signs and symptoms of toxicity develop rapidly, usually within the first hour of overdose. Manifestations of overdose include prolonged QTc, cardiac arrhythmias, tachycardia, hypertension, severe hypotension, agitation, seizures, central nervous system depression, hallucinations, seizures, and coma.

Overdose management includes activated charcoal, seizure control, cardioversion, hydration, electrolyte stabilization, and other intensive care.

OFF-LABEL TCA MANAGEMENT

Dosing recommendations for off-label use of TCAs vary based on the condition, the medication, and the suggestions of individual authors and researchers. In general, dosing ranges for pain and other nondepression indications may be lower than for severe depression (Table 2).¹

As with any pharmacologic titration, monitoring for rate-limiting adverse effects is recommended. We suggest caution, tailoring the approach to the patient, and routinely assessing for adverse effects and other safety considerations.

In addition, we strongly recommend supplementing TCA therapy with nonpharmacologic strategies such as lifestyle changes, dietary modifications, exercise, physical therapy, and mental health optimization.

Most tricyclic antidepressants (TCAs) have US Food and Drug Administration approval for treatment of depression and anxiety disorders, but they are also a viable off-label option that should be considered by clinicians in specialties beyond psychiatry, especially for treating pain syndromes. Given the ongoing epidemic of opioid use disorder, increasing attention has been drawn to alternative strategies for chronic pain management, renewing an interest in the use of TCAs.

This review summarizes the pharmacologic properties of TCAs, their potential indications in conditions other than depression, and safety considerations.

BRIEF HISTORY OF TRICYCLICS

TCAs were originally designed in the 1950s and marketed later for treating depression. Due to their adverse effects and lethality in overdose quantities, over time they have been largely replaced by selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) in depression management. However, TCAs have been applied to conditions other than depression with varying degrees of efficacy and safety.

TCA PHARMACOLOGY

TCAs are absorbed in the small intestine and undergo first-pass metabolism in the liver. They bind extensively to proteins, leading to interactions with other protein-bound drugs. They are widely distributed throughout the systemic circulation because they are highly lipophilic, resulting in systemic effects including central nervous system manifestations.

Peak plasma concentration is at about 2 to 6 hours, and elimination half-life is around 24 hours for most agents, providing a long duration of action. Clearance depends on cytochrome P450 oxidative enzymes.¹

MECHANISMS OF ACTION

TCAs inhibit reuptake of norepinephrine and serotonin, resulting in accumulation of these neurotransmitters in the presynaptic cleft. They also block postsynaptic histamine, alpha-adrenergic, and muscarinic-acetylcholine receptors, causing a variety of adverse effects, including dry mouth, confusion, cognitive impairment, hypotension, orthostasis, blurred vision, urinary retention, drowsiness, and sedation.¹

Research suggests that TCAs relieve pain centrally through a descending pathway that inhibits transmission of pain signals in the spinal cord, as well as peripherally through complex anti-neuroimmune actions.² Norepinephrine appears to play a more important role in this process than serotonin, although both are deemed necessary for the “dual action” often cited in pain management,¹ which is also the rationale for widespread use of SNRIs to control pain.

Table 1 compares neurotransmitter reuptake mechanisms, adverse effect profiles, and typical dosages for depression for commonly prescribed TCAs.

POTENTIAL USES

Headache and migraine

TCAs have been shown to be effective for managing and preventing chronic headache syndromes.^3,4 Amitriptyline has been the most studied of the TCAs for both chronic daily and episodic migraine headache, showing the most efficacy among diverse drug classes (angiotensin II receptor blockers, anticonvulsants, beta-blockers, SSRIs) compared with placebo. However, in head-to-head trials, amitriptyline was no more effective than SSRIs, venlafaxine, topiramate, or propranolol.⁴ Jackson et al⁴ suggested that prophylactic medication choices should be tailored to patient characteristics and expected adverse effects, and specifically recommended that TCAs—particularly amitriptyline—be reserved for patients who have both migraine and depression.

Neuropathic pain

Neuropathic pain is defined as pain secondary to a lesion or disease of the somatosensory nervous system⁵ and is the pathomechanistic component of a number of conditions, including postherpetic neuralgia,⁶ diabetic and nondiabetic painful polyneuropathy,⁷ posttraumatic or postsurgical neuropathic pain⁸ (including plexus avulsion and complex regional pain syndrome⁹), central poststroke pain,¹⁰ spinal cord injury pain,¹¹ and multiple sclerosis-associated pain.¹²

As a group, TCAs appear to have a role as first-line agents for managing these varied neuropathic pain syndromes. In a recent meta-analysis,¹³ 16 (89%) of 18 placebo-controlled trials of TCAs (mainly amitriptyline at 25–150 mg/day) for these pain conditions were positive, with a combined number needed to treat of 3.6, suggesting a role for TCAs in these conditions. Of note, the TCAs desipramine¹⁴ and nortriptyline¹⁵ have demonstrated little evidence of efficacy in neuropathic pain syndromes.

Chronic low back pain

Chronic low back pain is a leading cause of loss of work, excessive healthcare expenditure, and disability in the United States. It can be due to numerous spinal conditions, including degenerative disk disease, spinal stenosis, lumbar spondylosis, and spinal arthropathy.

TCAs have been used to treat chronic low back pain for decades and have been repeatedly shown to be more effective than placebo in reducing pain severity.^16,17 A double-blind controlled trial¹⁸ from 1999 compared the effects of the TCA maprotiline (up to 150 mg daily), the SSRI paroxetine (up to 30 mg daily), and placebo and found a statistically significant reduction in back pain with maprotiline compared with paroxetine and placebo. However, a 2008 meta-analysis suggested little evidence that TCAs were superior to placebo.¹⁹

Evidence of TCA efficacy for back pain was reported in 2018 with a well-designed 6-month double-blind randomized controlled trial²⁰ comparing low-dose amitriptyline (25 mg) with an active comparator (benztropine 1 mg). The authors reported that amitriptyline was effective in reducing pain and pain-related disability without incurring serious adverse effects. They suggested continued use of TCAs for chronic low back pain if complicated with pain-related disability, insomnia, depression, or other comorbidity, although they called for further large-scale studies. They also cautioned that patients started the trial with symptoms similar to the adverse effects of TCAs themselves; this has implications for monitoring of symptoms as well as TCA adverse effects while using these drugs.

Fibromyalgia is a common, frustrating, noninflammatory pain syndrome characterized by diffuse hyperalgesia and multiple comorbidities.²¹ Although sleep hygiene, exercise, cognitive-behavioral therapy, some gabapentinoids (pregabalin), and a combination of these therapies have demonstrated efficacy, TCAs also offer robust benefits.

A meta-analysis of 9 placebo-controlled TCA trials showed large effect sizes for pain reduction, fatigue reduction, improved sleep quality, and reduced stiffness and tenderness, with the most significant of these improvements being for sleep.²² A separate meta-analysis calculated that the number needed to treat with amitriptyline for a positive outcome is 4.9.²³ Recent systematic reviews have supported these findings, listing TCAs as second-line agents after pregabalin, duloxetine, and milnacipran.²⁴

Of note, TCA monotherapy rarely produces a complete response in patients with moderate to severe fibromyalgia, chronic widespread pain, or significant comorbidities (depression, anxiety). Supplementation with cognitive-behavioral therapy, physical therapy, functional restoration, and other modalities is strongly recommended.

Abdominal and gastrointestinal pain

TCAs have been applied to a number of gastrointestinal syndromes with or without pain. Patients with irritable bowel syndrome have long been known to benefit from TCAs; the number needed to treat for symptomatic benefit over placebo is 3.5.^25,26

Although there is no substantial evidence that TCAs are useful in reducing active inflammation in inflammatory bowel disease, a study involving 81 patients found that residual noninflammatory gastrointestinal symptoms (such as diarrhea and pain) responded to TCAs, including nortriptyline and amitriptyline, with greater benefit for ulcerative colitis than for Crohn disease.²⁷

TCAs have also shown prophylactic benefit in cyclic vomiting syndrome, with a clinical response in over 75% of patients in controlled cohort studies.²⁸

The efficacy of TCAs in other abdominal or gastrointestinal syndromes is unclear or modest at best.²⁹ However, few alternative treatments exist for these conditions. Amitriptyline may help symptoms of functional dyspepsia,³⁰ but nortriptyline has proven ineffective in gastroparesis.³¹ Nonetheless, some authors²⁹ suggest considering TCAs on an individualized basis, with proper monitoring, in many if not most functional gastrointestinal disorders, especially when paired with behavioral therapies.

Pelvic and urogynecologic symptoms

Chronic pelvic pain affects up to 24% of women³² and 5% to 10% of men.³³ TCAs have shown efficacy in treating chronic pelvic pain with or without comorbid depression.³⁴ Amitriptyline and to a lesser extent nortriptyline are the TCAs most often prescribed. Pain relief appears to be independent of antidepressant effects and may be achieved at low doses; initial dosing ranges from 10 to 25 mg at bedtime, which may be increased to 100 mg as tolerated.³⁴

Based on a randomized, double-blind trial,³⁵ amitriptyline was recommended as a treatment option for interstitial cystitis or bladder pain, with the greatest symptom improvement in patients tolerating a daily dose of 50 mg.

Another study³⁶ randomized 56 women with chronic pelvic pain to amitriptyline or  gabapentin, or a combination of the drugs for 24 months. Although each regimen resulted in significant reduction in pain, fewer adverse effects occurred with gabapentin than amitriptyline. Poor compliance and early discontinuation of amitriptyline were common due to anticholinergic effects.

In small uncontrolled studies,³⁷ about half of women with chronic pelvic pain became pain-free after 8 weeks of treatment with nortriptyline and imipramine.

Randomized controlled studies are needed to confirm potential benefits of TCAs in chronic urologic and pelvic pain.

Insomnia

Insomnia affects 23% to 56% of people in the United States, Europe, and Asia³⁸ and is the reason for more than 5.5 million primary care visits annually.³⁹ TCAs (especially doxepin, maprotiline, and amitriptyline⁴⁰) have been shown to be an effective treatment, with an 82% increase in somnolence compared with placebo, as well as measurably improved total sleep time, enhanced sleep efficiency, reduced latency to persistent sleep, and decreased wake times after sleep onset.³⁸

Dosing should be kept at a minimum to minimize harsh anticholinergic effects and avoid daytime sedation. Patients should be advised to take new doses or dose escalations earlier in the night to ensure less hangover sedation the next morning.

For patients with insomnia and comorbid depression, the American Academy of Sleep Medicine suggests the addition of a low dose (eg, 10–25 mg) of a TCA at nighttime to complement preexisting, full-dose, non-TCA antidepressants, while monitoring for serotonin syndrome and other potential but exceedingly rare drug-drug interactions.⁴¹

Psychiatric indications other than depression

Beyond the known benefits in major depressive disorder, TCAs have been shown to be effective for obsessive-compulsive disorder, panic disorder, posttraumatic stress disorder, bulimia nervosa, and childhood enuresis.⁴² Given the shortage of mental health clinicians and the high prevalence of these conditions, nonpsychiatrist physicians should be familiar with the therapeutic potential of TCAs for these indications.

ADVERSE EFFECTS

Adverse effects vary among TCAs. Common ones include blurred vision, dry mouth, constipation, urinary retention, hypotension, tachycardia, tremor, weight gain, and sexual dysfunction.⁴³ Tertiary amines are generally more sedating than secondary amines and cause more anticholinergic effects (Table 1).

Despite widespread perceptions that TCAs are less tolerable than newer antidepressants, studies repeatedly suggest that they have an adverse-effect burden similar to that of SSRIs and SNRIs, although SSRIs have a greater tendency to produce nausea, whereas TCAs are more likely to cause constipation.⁴⁴

Discontinuation syndrome

Abrupt discontinuation or unintentionally missed doses of TCAs have been associated with a discontinuation syndrome in about 40% of users.⁴⁵ Patients should be warned about this possibility and the syndrome’s potential effects: dizziness, insomnia, headaches, nausea, vomiting, flulike achiness, and restlessness. Rebound depression, anxiety, panic, or other psychiatric symptoms may also occur. Symptoms generally present within 2 to 5 days after dose discontinuation and last 7 to 14 days.⁴⁵

However, all TCAs have a long half-life, allowing for sufficient coverage with once-daily dosing and thus carry a lower risk of discontinuation syndrome than many other antidepressants (78% with venlafaxine; 55% with paroxetine).⁴⁵

To discontinue therapy safely, the dosage should be reduced gradually. As is pharmacologically expected, the greatest likelihood of discontinuation syndrome is associated with longer duration of continuous treatment.

CONTRAINDICATIONS

Cardiac conduction abnormalities

TCAs should not be prescribed to patients who have right bundle branch block, a severe electrolyte disturbance, or other cardiac conduction deficit or arrhythmia that can prolong the QTc interval and elevate the risk of lethal arrhythmia.^46,47 Cardiac effects from TCAs are largely dose-dependent. Nevertheless, a baseline electrocardiogram can be obtained to assess cardiac risk, and dose escalation can proceed if results are normal (eg, appropriate conduction intervals, QTc ≤ 450 ms).

Advanced age

For elderly patients, TCAs should be prescribed with caution and sometimes not at all,⁴⁸ because anticholinergic effects may worsen preexisting urinary retention (including benign prostatic hyperplasia), narrow-angle glaucoma, imbalance and gait issues, and cognitive impairment and dementia. Dehydration and orthostatic hypotension are contraindications for TCAs, as they may precipitate falls or hypotensive shock.

Epilepsy

TCAs should also be used with caution in patients with epilepsy, as they lower the seizure threshold.

Concomitant monoamine oxidase inhibitor treatment

Giving TCAs together with monoamine oxidase inhibitor antidepressants should be avoided, given the risk of hypertensive crisis.

Suicide risk

TCAs are dangerous and potentially lethal in overdose and so should not be prescribed to suicidal or otherwise impulsive patients.

Pregnancy

TCAs are in pregnancy risk category C (animal studies show adverse effects on fetus; no adequate or well-controlled studies in humans; potential benefits may warrant use despite risks). Using TCAs during pregnancy has very rarely led to neonatal withdrawal such as irritability, jitteriness, and convulsions, as well as fetal QTc interval prolongation.⁴⁹

The American College of Obstetricians and Gynecologists recommends that therapy for depression during pregnancy be individualized, incorporating the expertise of the patient’s mental health clinician, obstetrician, primary healthcare provider, and pediatrician. In general, they recommend that TCAs should be avoided if possible and that alternatives such as SSRIs or SNRIs should be considered.⁵⁰

TCAs are excreted in breast milk, but they have not been detected in the serum of nursing infants, and no adverse events have been reported.

OVERDOSE IS HIGHLY DANGEROUS

Severe morbidity and death are associated with TCA overdose, characterized by  convulsions, cardiac arrest, and coma (the “3 Cs”). These dangers occur at much higher rates with TCAs than with other antidepressants.⁴³ Signs and symptoms of toxicity develop rapidly, usually within the first hour of overdose. Manifestations of overdose include prolonged QTc, cardiac arrhythmias, tachycardia, hypertension, severe hypotension, agitation, seizures, central nervous system depression, hallucinations, seizures, and coma.

Overdose management includes activated charcoal, seizure control, cardioversion, hydration, electrolyte stabilization, and other intensive care.

OFF-LABEL TCA MANAGEMENT

Dosing recommendations for off-label use of TCAs vary based on the condition, the medication, and the suggestions of individual authors and researchers. In general, dosing ranges for pain and other nondepression indications may be lower than for severe depression (Table 2).¹

As with any pharmacologic titration, monitoring for rate-limiting adverse effects is recommended. We suggest caution, tailoring the approach to the patient, and routinely assessing for adverse effects and other safety considerations.

In addition, we strongly recommend supplementing TCA therapy with nonpharmacologic strategies such as lifestyle changes, dietary modifications, exercise, physical therapy, and mental health optimization.

Perceptions regarding the use of gabapentin for alcohol use disorder (AUD) have shifted over time.^1–4 Early on, the drug was deemed to be benign and effective.^4–6 But more and more, concerns are being raised about its recreational use to achieve euphoria,⁷ and the drug is often misused by vulnerable populations, particularly those with opioid use disorder.^7–9

Given the large number of gabapentin prescriptions written off-label for AUD, it is incumbent on providers to understand how to prescribe it responsibly.^7–9 To that end, this article focuses on the benefits—and concerns—of this treatment option. We describe the effects of gabapentin on the central nervous system and how it may mitigate alcohol withdrawal and increase the likelihood of abstinence. In addition, we review clinical trials that evaluated potential roles of gabapentin in AUD, discuss the drug’s misuse potential, and suggest a framework for its appropriate use in AUD management.

ALCOHOL USE DISORDER IS COMMON AND SERIOUS

AUD affects about 14% of US adults and represents a significant health burden,¹ often with severe clinical and social implications. It manifests as compulsive drinking and loss of control despite adverse consequences on various life domains.¹⁰ It is generally associated with cravings, tolerance, and withdrawal symptoms upon cessation. Alcohol withdrawal is characterized by tremors, anxiety, sweating, nausea, and tachycardia, and in severe cases, may involve hallucinations, seizures, and delirium tremens. Untreated, alcohol withdrawal can be fatal.¹⁰

Even though psychosocial treatments for AUD by themselves are associated with high relapse rates, pharmacotherapy is underutilized. Three drugs approved by the US Food and Drug Administration (FDA) are available to treat it, but they are often poorly accepted and have limited efficacy. For these reasons, there is considerable interest in finding alternatives. Gabapentin is one of several agents that have been studied (Table 1). The topic has been reviewed in depth by Soyka and Müller.¹¹

GABAPENTIN REDUCES EXCITATION

The anticonvulsant gabapentin is FDA-approved for treating epilepsy, postherpetic neuralgia, and restless leg syndrome.^8,12–14 It binds and selectively impedes voltage-sensitive calcium channels, the pores in cell membrane that permit calcium to enter a neuron in response to changes in electrical currents.¹⁵

Gabapentin is believed to decrease excitation of the central nervous system in multiple ways:

• It reduces the release of glutamate, a key component of the excitatory system¹⁶
• It increases the concentration of gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the brain7
• By binding the alpha-2-delta type 1 subunit of voltage-sensitive calcium channels,^8,15–17 it inhibits excitatory synapse formation independent of calcium channel activity¹⁶
• By blocking excitatory neurotransmission, it also may indirectly increase the concentration of GABA in the central nervous system1^6,17
• It modulates action of glutamic acid decarboxylase (involved in the synthesis of GABA) and glutamate synthesizing enzyme to increase GABA and decrease glutamate.¹⁷

The actions of alcohol on the brain are also complex.¹⁸ Alpha-2-delta type 1 subunits of calcium channels are upregulated in the reward centers of the brain by addictive substances, including alcohol.¹⁶ Alcohol interacts with corticotropin-releasing factor and several neurotransmitters,¹⁸ and specifically affects neuropathways involving norepinephrine, GABA, and glutamate.¹⁹ Alcohol has reinforcing effects mediated by the release of dopamine in the nucleus accumbens.²⁰

Acutely, alcohol promotes GABA release and may also reduce GABA degradation, producing sedative and anxiolytic effects.²¹ Chronic alcohol use leads to a decrease in the number of GABAA receptors. Clinically, this downregulation manifests as tolerance to alcohol’s sedating effects.²¹

Alcohol affects the signaling of glutamatergic interaction with the N-methyl-d-aspartate (NMDA) receptor.²² Glutamate activates this receptor as well as the voltage-gated ion channels, modifying calcium influx and increasing neuronal excitability.^22,23 Acutely, alcohol has an antagonistic effect on the NMDA receptor, while chronic drinking upregulates (increases) the number of NMDA receptors and voltage-gated calcium channels.^22,23

Alcohol withdrawal increases excitatory effects

Patients experiencing alcohol withdrawal have decreased GABA-ergic functioning and increased glutamatergic action throughout the central nervous system.^19,24

Withdrawal can be subdivided into an acute phase (lasting up to about 5 days) and a protracted phase (of undetermined duration). During withdrawal, the brain activates its “stress system,” leading to overexpression of corticotropin-releasing factor in the amygdala. Protracted withdrawal dysregulates the prefrontal cortex, increasing cravings and worsening negative emotional states and sleep.¹⁶

GABAPENTIN FOR ALCOHOL WITHDRAWAL

Benzodiazepines are the standard treatment for alcohol withdrawal.^3,24 They relieve symptoms and can prevent seizures and delirium tremens,²⁴ but they are sedating and cause psychomotor impairments.³ Because of the potential for addiction, benzodiazepine use is limited to acute alcohol withdrawal.³

Gabapentin shows promise as an agent that can be used in withdrawal and continued through early abstinence without the highly addictive potential of benzodiazepines.¹⁶ It is thought to affect drinking behaviors during early abstinence by normalizing GABA and glutamate activity.^2,16

Early preclinical studies in mouse models found that gabapentin decreases anxiogenic and epileptic effects of alcohol withdrawal. Compared with other antidrinking medications, gabapentin has the benefits of lacking elimination via hepatic metabolism, few pharmacokinetic interactions, and good reported tolerability in this population.

Inpatient trials show no benefit over standard treatments

Bonnet et al²⁵ conducted a double-blind placebo-controlled trial in Germany in inpatients experiencing acute alcohol withdrawal to determine whether gabapentin might be an effective adjunct to clomethiazole, a GABAA modulator commonly used in Europe for alcohol withdrawal. Participants (N = 61) were randomized to receive placebo or gabapentin (400 mg every 6 hours) for 72 hours, with tapering over the next 3 days. All patients could receive rescue doses of clomethiazole, using a symptom-triggered protocol.

The study revealed no differences in the amount of clomethiazole administered between the 2 groups, suggesting that gabapentin had no adjunctive effect. Side effects (vertigo, nausea, dizziness, and ataxia) were mild and comparable between groups.

Nichols et al²⁶ conducted a retrospective cohort study in a South Carolina academic psychiatric hospital to assess the adjunctive effect of gabapentin on the as-needed use of benzodiazepines for alcohol withdrawal. The active group (n = 40) received gabapentin as well as a symptom-triggered alcohol withdrawal protocol of benzodiazepine. The control group (n = 43) received only the symptom-triggered alcohol withdrawal protocol without gabapentin.

No effect was found of gabapentin use for benzodiazepine treatment of alcohol withdrawal. It is notable that Bonnet et al and Nichols et al had similar findings despite their studies being conducted in different countries using distinct comparators and methods.

Bonnet et al,²⁷ in another study, tried a different design to investigate a possible role for gabapentin in inpatient alcohol withdrawal. The study included 37 patients with severe alcohol withdrawal (Clinical Institute Withdrawal Assessment of Alcohol Scale, Revised [CIWA-Ar] > 15).

All participants received gabapentin 800 mg. Those whose CIWA-Ar score improved within 2 hours were considered “early responders” (n = 27) and next received 2 days of gabapentin 600 mg 4 times a day before starting a taper. The nonresponders whose CIWA-Ar score worsened (associated with greater anxiety and depressive symptoms; n = 10) were switched to standard treatment with clomethiazole (n = 4) or clonazepam (n = 6). Scores of 3 early responders subsequently worsened; 2 of these participants developed seizures and were switched to standard treatment.

The authors concluded that gabapentin in a dose of 3,200 mg in the first 24 hours is useful only for milder forms of alcohol withdrawal. Hence, subsequent efforts on the use of gabapentin for alcohol withdrawal have focused on outpatients.

Outpatient trials reveal benefits over benzodiazepines

Myrick et al³ compared gabapentin vs lorazepam in 100 outpatients seeking treatment for alcohol withdrawal. Participants were randomized to 1 of 4 groups: gabapentin 600 mg, 900 mg, or 1,200 mg, or lorazepam 6 mg, each tapering over 4 days. Alcohol withdrawal was measured by the CIWA-Ar score. Only 68 patients completed all follow-up appointments to day 12.

Gabapentin 600 mg was discontinued because of seizures in 2 patients, but it was generally well tolerated and was associated with diminished symptoms of alcohol withdrawal, especially at the 1,200 mg dose. The gabapentin groups experienced less anxiety and sedation and fewer cravings than the lorazepam group. Those treated with lorazepam fared worse for achieving early abstinence and were more likely to return to drinking when the intervention was discontinued. However, significant relapse by day 12 occurred in both groups.

The authors concluded that gabapentin was at least as effective as lorazepam in the outpatient treatment of alcohol withdrawal, with the 1,200-mg gabapentin dosage being more effective than 900 mg. At 1,200 mg, gabapentin was associated with better sleep, less anxiety, and better self-reported ability to work than lorazepam, and at the 900-mg dose it was associated with less depression than lorazepam.

Stock et al²⁸ conducted a randomized, double-blind study of gabapentin in acute alcohol withdrawal in 26 military veterans in an outpatient setting. Patients were ran­domized to one of the following:

• Gabapentin 1,200 mg orally for 3 days, followed by 900 mg, 600 mg, and 300 mg for 1 day each (n = 17)
• Chlordiazepoxide 100 mg orally for 3 days, followed by 75 mg, 50 mg, and 25 mg for 1 day each (n = 9).

Withdrawal scores improved similarly in both groups. Early on (days 1–4), neither cravings nor sleep differed significantly between groups; but later (days 5–7), the gabapentin group had superior scores for these measures. Gabapentin was also associated with significantly less sedation than chlordiazepoxide and trended to less alcohol craving.

Data suggest that gabapentin offers benefits for managing mild alcohol withdrawal. Improved residual craving and sleep measures are clinically important because they are risk factors for relapse. Mood and anxiety also improve with gabapentin, further indicating a therapeutic effect.

Gabapentin’s benefits for moderate and severe alcohol withdrawal have not been established. Seizures occurred during withdrawal despite gabapentin treatment, but whether from an insufficient dose, patient susceptibility, or lack of gabapentin efficacy is not clear. Best results occurred at the 1,200-mg daily dose, but benefits may not apply to patients with severe withdrawal. In addition, many studies were small, limiting the strength of conclusions.

Across most studies of gabapentin for alcohol withdrawal, advantages included a smoother transition into early abstinence due to improved sleep, mood, and anxiety, alleviating common triggers for a return to drinking. Gabapentin also carries less reinforcing potential than benzodiazepines. These qualities fueled interest in trying gabapentin to improve long-term abstinence.

GABAPENTIN FOR RELAPSE PREVENTION

Although naltrexone and acamprosate are the first-line treatments for relapse prevention, they do not help all patients and are more effective when combined with cognitive behavioral therapy.^1,29,30 For patients in whom standard treatments are not effective or tolerated, gabapentin may provide a reasonable alternative, and several randomized controlled trials have examined its use for this role.

Gabapentin alone is better than placebo

Furieri and Nakamura-Palacios⁴ assessed the use of gabapentin for relapse prevention in Brazilian outpatients (N = 60) who had averaged 27 years of drinking and consumed 17 drinks daily for the 90 days before baseline. After detoxification with diazepam and vitamins, patients were randomized to either gabapentin 300 mg twice daily or placebo for 4 weeks.

Compared with placebo, gabapentin significantly reduced cravings and lowered the percentage of heavy drinking days and the number of drinks per day, with a significant increase in the percentage of abstinent days. These self-reported measures correlated with decreases in gamma-glutamyl transferase, a biological marker for heavy drinking.

Brower et al³¹ investigated the use of gabapentin in 21 outpatients with AUD and insomnia who desired to remain abstinent. They were randomized to gabapentin (up to 1,500 mg at night) or placebo for 6 weeks. Just 14 participants completed the study; all but 2 were followed without treatment until week 12.

Gabapentin was associated with significantly lower relapse rates at 6 weeks (3 of 10 in the gabapentin group vs 9 of 11 in the placebo group) and at 12 weeks (6 of 10 in the gabapentin group vs 11 of 11 in the placebo group, assuming the 2 patients lost to follow-up relapsed). No difference between groups was detected for sleep measures in this small study. However, other studies have found that gabapentin for AUD improves measures of insomnia and daytime drowsiness—predictors of relapse—compared with other medications.¹⁶

High-dose gabapentin is better

Mason et al² randomized 150 outpatients with alcohol dependence to 12 weeks of daily treatment with either gabapentin (900 mg or 1,800 mg) or placebo after at least 3 days of abstinence. All participants received counseling. Drinking quantity and frequency were assessed by gamma-glutamyl transferase testing.

Patients taking gabapentin had better rates of abstinence and cessation of heavy drinking than those taking placebo. During the 12-week study, the 1,800-mg daily dose showed a substantially higher abstinence rate (17%) than either 900 mg  (11%) or placebo (4%). Significant dose-related improvements were also found for heavy drinking days, total drinking quantity, and frequency of alcohol withdrawal symptoms that predispose to early relapse, such as poor sleep, cravings, and poor mood. There were also significant linear dose effects on rates of abstinence and nondrinking days at the 24-week posttreatment follow-up.

Gabapentin plus naltrexone is better than naltrexone alone

Anton et al⁵ examined the efficacy of gabapentin combined with naltrexone during early abstinence. The study randomly assigned 150 people with AUD to one of the following groups:

• 16 weeks of naltrexone (50 mg/day) alone
• 6 weeks of naltrexone (50 mg/day) plus gabapentin (up to 1,200 mg/day), followed by 10 weeks of naltrexone alone
• Placebo.

All participants received medical management.

Over the first 6 weeks, those receiving naltrexone plus gabapentin had a longer interval to heavy drinking than those taking only naltrexone. By week 6, about half of those taking placebo or naltrexone alone had a heavy drinking day, compared with about 35% of those taking naltrexone plus gabapentin. Those receiving the combination also had fewer days of heavy drinking, fewer drinks per drinking day, and better sleep than the other groups. Participants in the naltrexone-alone group were more likely to drink heavily during periods in which they reported poor sleep. No significant group differences were found in measures of mood.

Gabapentin enacarbil is no better than placebo

Falk et al,³² in a 2019 preliminary analysis, examined data from a trial of gabapentin enacarbil, a prodrug formulation of gabapentin. In this 6-month double-blind study, 346 people with moderate AUD at 10 sites were randomized to gabapentin enacarbil extended-release 600 mg twice a day or placebo. All subjects received a computerized behavioral intervention.

No significant differences between groups were found in drinking measures or alcohol cravings, sleep problems, depression, or anxiety symptoms. However, a dose-response analysis found significantly less drinking for higher doses of the drug.

Bottom line: Evidence of benefits mixed but risk low

The efficacy of gabapentin as a treatment for AUD has varied across studies as a function of dosing and formulation. Daily doses have ranged from 600 mg to 1,800 mg, with the highest dose showing advantages in one study for cravings, insomnia, anxiety, dysphoria, and relapse.² Thus far, gabapentin immediate-release has performed better than gabapentin enacarbil extended-release. All forms of gabapentin have been well-tolerated in AUD trials.

The 2018 American Psychiatric Association guidelines stated that gabapentin had a small positive effect on drinking outcomes, but the harm of treatment was deemed minimal, especially relative to the harms of chronic drinking.³³ The guidelines endorse the use of gabapentin in patients with moderate to severe AUD who select gabapentin from the available options, or for those who are nonresponsive to or cannot tolerate naltrexone or acamprosate, as long as no contraindications exist. It was also noted that even small effects may be clinically important, considering the significant morbidity associated with AUD.

The use of gabapentin has become controversial owing to the growing recognition that it may not be as benign as initially thought.^7–9,34 A review of US legislative actions reflects concerns about its misuse.³⁵ In July 2017, Kentucky classified it as a schedule V controlled substance with prescription drug monitoring,³⁵ as did Tennessee in 2018³⁶ and Michigan in January 2019.³⁷ Currently, 8 other states (Massachusetts, Minnesota, Nebraska, North Dakota, Ohio, Virginia, Wyoming, and West Virginia) require prescription drug monitoring of gabapentin, and other states are considering it.³⁵

Efforts to understand gabapentin misuse derive largely from people with drug use disorders. A review of postmortem toxicology reports in fatal drug overdoses found gabapentin present in 22%.³⁸ Although it was not necessarily a cause of death, its high rate of detection suggests wide misuse among drug users.

Among a cohort of 503 prescription opioid misusers in Appalachian Kentucky, 15% reported using gabapentin “to get high.” Those who reported misusing gabapentin were 6 times more likely than nonusers to be abusing opioids and benzodiazepines. The main sources of gabapentin were doctors (52%) and dealers (36%). The average cost of gabapentin on the street was less than $1.00 per pill.³⁹

Gabapentin misuse by methadone clinic patients is also reported. Baird et al⁴⁰ surveyed patients in 6 addiction clinics in the United Kingdom for gabapentin and pregabalin abuse and found that 22% disclosed misusing these medications. Of these, 38% said they did so to enhance the methadone high.

In a review article, Quintero⁴¹ also cited enhancement of methadone euphoria and treatment of opioid withdrawal as motivations for misuse. Opioid-dependent gabapentin misusers consumed doses of gabapentin 3 to 20 times higher than clinically recommended and in combination with multiple drugs.⁴ Such use can cause dissociative and psychedelic effects.

Gabapentin also potentiates the sedative effects of opioids, thus increasing the risk of falls, accidents, and other adverse events.^34,35 Risk of opioid-related deaths was increased with coprescription of gabapentin and with moderate to high gabapentin doses.³⁴

Are people with AUD at higher risk of gabapentin abuse?

Despite concerns, patients in clinical trials of gabapentin treatment for AUD were not identified as at high risk for misuse of the drug.^2,4,5,16 Further, no such trials reported serious drug-related adverse events resulting in gabapentin discontinuation or side effects that differed from placebo in frequency or severity.^2,4,5,16

Clinical laboratory studies also have found no significant interactions between alcohol and gabapentin.^42,43 In fact, they showed no influence of gabapentin on the pharmacokinetics of alcohol or on alcohol’s subjective effects. Relative to placebo, gabapentin did not affect blood alcohol levels, the degree of intoxication, sedation, craving, or alcohol self-administration.

Smith et al⁹ reported estimates that only 1% of the general population misuse gabapentin. Another review concluded that gabapentin is seldom a drug of choice.¹⁷ Most patients prescribed gabapentin do not experience cravings or loss of control, which are hallmarks of addiction. Hence, with adequate precautions, the off-label use of gabapentin for AUD is reasonable.

CLINICAL IMPLICATIONS OF GABAPENTIN PRESCRIBING

Overall, evidence for the benefit of gabapentin in AUD is mixed. Subgroups of alcoholic patients, such as those who do not respond to or tolerate standard therapies, may particularly benefit, as may those with comorbid insomnia or neuropathic pain.⁴⁴ Clinicians should prescribe gabapentin only when it is likely to be helpful and should carefully document its efficacy.^2,45

At each visit, an open and honest assessment of the benefits and risks serves to promote shared decision-making regarding initiating, continuing, or discontinuing gabapentin.

For alcohol withdrawal

Before gabapentin is prescribed for alcohol withdrawal, potential benefits (reduction of withdrawal symptoms), side effects (sedation, fatigue), and risks (falls) should be discussed with the patient.⁴⁶ Patients should also be informed that benzodiazepines are the gold standard for alcohol withdrawal and that gabapentin is not effective for severe withdrawal.⁴⁶

For relapse prevention

When initiating treatment for relapse prevention, the patient and the prescriber should agree on specific goals (eg, reduction of drinking, anxiety, and insomnia).^2,16 Ongoing monitoring is essential and includes assessing and documenting improvement with respect to these goals.

In the AUD studies, gabapentin was well tolerated.¹⁶ Frequently observed side effects including headache, insomnia, fatigue, muscle aches, and gastrointestinal distress did not occur at a statistically different rate from placebo. However, patients in studies are selected samples, and their experience may not be generalizable to clinical practice. Thus, it is necessary to exercise caution and check for comorbidities that may put patients at risk of complications.⁴⁷ Older patients and those on hemodialysis are more susceptible to gabapentin side effects such as sedation, dizziness, ataxia, and mental status changes,³⁴ and prescribers should be alert for signs of toxicity (eg, ataxia, mental status changes).^47,48

Gabapentin misuse was not observed in AUD studies,^2,4,5,16 but evidence indicates that patients with opioid use disorder, prisoners, and polydrug users are at high risk for gabapentin misuse.^39–41 In all cases, clinicians should monitor for red flags that may indicate abuse, such as missed appointments, early refill requests, demands for increased dosage, and simultaneous opiate and benzodiazepine use.⁴⁹

Acknowledgment: The authors wish to thank Nick Mulligan for his invaluable assistance with formatting and grammar.

Perceptions regarding the use of gabapentin for alcohol use disorder (AUD) have shifted over time.^1–4 Early on, the drug was deemed to be benign and effective.^4–6 But more and more, concerns are being raised about its recreational use to achieve euphoria,⁷ and the drug is often misused by vulnerable populations, particularly those with opioid use disorder.^7–9

Given the large number of gabapentin prescriptions written off-label for AUD, it is incumbent on providers to understand how to prescribe it responsibly.^7–9 To that end, this article focuses on the benefits—and concerns—of this treatment option. We describe the effects of gabapentin on the central nervous system and how it may mitigate alcohol withdrawal and increase the likelihood of abstinence. In addition, we review clinical trials that evaluated potential roles of gabapentin in AUD, discuss the drug’s misuse potential, and suggest a framework for its appropriate use in AUD management.

ALCOHOL USE DISORDER IS COMMON AND SERIOUS

AUD affects about 14% of US adults and represents a significant health burden,¹ often with severe clinical and social implications. It manifests as compulsive drinking and loss of control despite adverse consequences on various life domains.¹⁰ It is generally associated with cravings, tolerance, and withdrawal symptoms upon cessation. Alcohol withdrawal is characterized by tremors, anxiety, sweating, nausea, and tachycardia, and in severe cases, may involve hallucinations, seizures, and delirium tremens. Untreated, alcohol withdrawal can be fatal.¹⁰

Even though psychosocial treatments for AUD by themselves are associated with high relapse rates, pharmacotherapy is underutilized. Three drugs approved by the US Food and Drug Administration (FDA) are available to treat it, but they are often poorly accepted and have limited efficacy. For these reasons, there is considerable interest in finding alternatives. Gabapentin is one of several agents that have been studied (Table 1). The topic has been reviewed in depth by Soyka and Müller.¹¹

GABAPENTIN REDUCES EXCITATION

The anticonvulsant gabapentin is FDA-approved for treating epilepsy, postherpetic neuralgia, and restless leg syndrome.^8,12–14 It binds and selectively impedes voltage-sensitive calcium channels, the pores in cell membrane that permit calcium to enter a neuron in response to changes in electrical currents.¹⁵

Gabapentin is believed to decrease excitation of the central nervous system in multiple ways:

• It reduces the release of glutamate, a key component of the excitatory system¹⁶
• It increases the concentration of gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the brain7
• By binding the alpha-2-delta type 1 subunit of voltage-sensitive calcium channels,^8,15–17 it inhibits excitatory synapse formation independent of calcium channel activity¹⁶
• By blocking excitatory neurotransmission, it also may indirectly increase the concentration of GABA in the central nervous system1^6,17
• It modulates action of glutamic acid decarboxylase (involved in the synthesis of GABA) and glutamate synthesizing enzyme to increase GABA and decrease glutamate.¹⁷

The actions of alcohol on the brain are also complex.¹⁸ Alpha-2-delta type 1 subunits of calcium channels are upregulated in the reward centers of the brain by addictive substances, including alcohol.¹⁶ Alcohol interacts with corticotropin-releasing factor and several neurotransmitters,¹⁸ and specifically affects neuropathways involving norepinephrine, GABA, and glutamate.¹⁹ Alcohol has reinforcing effects mediated by the release of dopamine in the nucleus accumbens.²⁰

Acutely, alcohol promotes GABA release and may also reduce GABA degradation, producing sedative and anxiolytic effects.²¹ Chronic alcohol use leads to a decrease in the number of GABAA receptors. Clinically, this downregulation manifests as tolerance to alcohol’s sedating effects.²¹

Alcohol affects the signaling of glutamatergic interaction with the N-methyl-d-aspartate (NMDA) receptor.²² Glutamate activates this receptor as well as the voltage-gated ion channels, modifying calcium influx and increasing neuronal excitability.^22,23 Acutely, alcohol has an antagonistic effect on the NMDA receptor, while chronic drinking upregulates (increases) the number of NMDA receptors and voltage-gated calcium channels.^22,23

Alcohol withdrawal increases excitatory effects

Patients experiencing alcohol withdrawal have decreased GABA-ergic functioning and increased glutamatergic action throughout the central nervous system.^19,24

Withdrawal can be subdivided into an acute phase (lasting up to about 5 days) and a protracted phase (of undetermined duration). During withdrawal, the brain activates its “stress system,” leading to overexpression of corticotropin-releasing factor in the amygdala. Protracted withdrawal dysregulates the prefrontal cortex, increasing cravings and worsening negative emotional states and sleep.¹⁶

GABAPENTIN FOR ALCOHOL WITHDRAWAL

Benzodiazepines are the standard treatment for alcohol withdrawal.^3,24 They relieve symptoms and can prevent seizures and delirium tremens,²⁴ but they are sedating and cause psychomotor impairments.³ Because of the potential for addiction, benzodiazepine use is limited to acute alcohol withdrawal.³

Gabapentin shows promise as an agent that can be used in withdrawal and continued through early abstinence without the highly addictive potential of benzodiazepines.¹⁶ It is thought to affect drinking behaviors during early abstinence by normalizing GABA and glutamate activity.^2,16

Early preclinical studies in mouse models found that gabapentin decreases anxiogenic and epileptic effects of alcohol withdrawal. Compared with other antidrinking medications, gabapentin has the benefits of lacking elimination via hepatic metabolism, few pharmacokinetic interactions, and good reported tolerability in this population.

Inpatient trials show no benefit over standard treatments

Bonnet et al²⁵ conducted a double-blind placebo-controlled trial in Germany in inpatients experiencing acute alcohol withdrawal to determine whether gabapentin might be an effective adjunct to clomethiazole, a GABAA modulator commonly used in Europe for alcohol withdrawal. Participants (N = 61) were randomized to receive placebo or gabapentin (400 mg every 6 hours) for 72 hours, with tapering over the next 3 days. All patients could receive rescue doses of clomethiazole, using a symptom-triggered protocol.

The study revealed no differences in the amount of clomethiazole administered between the 2 groups, suggesting that gabapentin had no adjunctive effect. Side effects (vertigo, nausea, dizziness, and ataxia) were mild and comparable between groups.

Nichols et al²⁶ conducted a retrospective cohort study in a South Carolina academic psychiatric hospital to assess the adjunctive effect of gabapentin on the as-needed use of benzodiazepines for alcohol withdrawal. The active group (n = 40) received gabapentin as well as a symptom-triggered alcohol withdrawal protocol of benzodiazepine. The control group (n = 43) received only the symptom-triggered alcohol withdrawal protocol without gabapentin.

No effect was found of gabapentin use for benzodiazepine treatment of alcohol withdrawal. It is notable that Bonnet et al and Nichols et al had similar findings despite their studies being conducted in different countries using distinct comparators and methods.

Bonnet et al,²⁷ in another study, tried a different design to investigate a possible role for gabapentin in inpatient alcohol withdrawal. The study included 37 patients with severe alcohol withdrawal (Clinical Institute Withdrawal Assessment of Alcohol Scale, Revised [CIWA-Ar] > 15).

All participants received gabapentin 800 mg. Those whose CIWA-Ar score improved within 2 hours were considered “early responders” (n = 27) and next received 2 days of gabapentin 600 mg 4 times a day before starting a taper. The nonresponders whose CIWA-Ar score worsened (associated with greater anxiety and depressive symptoms; n = 10) were switched to standard treatment with clomethiazole (n = 4) or clonazepam (n = 6). Scores of 3 early responders subsequently worsened; 2 of these participants developed seizures and were switched to standard treatment.

The authors concluded that gabapentin in a dose of 3,200 mg in the first 24 hours is useful only for milder forms of alcohol withdrawal. Hence, subsequent efforts on the use of gabapentin for alcohol withdrawal have focused on outpatients.

Outpatient trials reveal benefits over benzodiazepines

Myrick et al³ compared gabapentin vs lorazepam in 100 outpatients seeking treatment for alcohol withdrawal. Participants were randomized to 1 of 4 groups: gabapentin 600 mg, 900 mg, or 1,200 mg, or lorazepam 6 mg, each tapering over 4 days. Alcohol withdrawal was measured by the CIWA-Ar score. Only 68 patients completed all follow-up appointments to day 12.

Gabapentin 600 mg was discontinued because of seizures in 2 patients, but it was generally well tolerated and was associated with diminished symptoms of alcohol withdrawal, especially at the 1,200 mg dose. The gabapentin groups experienced less anxiety and sedation and fewer cravings than the lorazepam group. Those treated with lorazepam fared worse for achieving early abstinence and were more likely to return to drinking when the intervention was discontinued. However, significant relapse by day 12 occurred in both groups.

The authors concluded that gabapentin was at least as effective as lorazepam in the outpatient treatment of alcohol withdrawal, with the 1,200-mg gabapentin dosage being more effective than 900 mg. At 1,200 mg, gabapentin was associated with better sleep, less anxiety, and better self-reported ability to work than lorazepam, and at the 900-mg dose it was associated with less depression than lorazepam.

Stock et al²⁸ conducted a randomized, double-blind study of gabapentin in acute alcohol withdrawal in 26 military veterans in an outpatient setting. Patients were ran­domized to one of the following:

• Gabapentin 1,200 mg orally for 3 days, followed by 900 mg, 600 mg, and 300 mg for 1 day each (n = 17)
• Chlordiazepoxide 100 mg orally for 3 days, followed by 75 mg, 50 mg, and 25 mg for 1 day each (n = 9).

Withdrawal scores improved similarly in both groups. Early on (days 1–4), neither cravings nor sleep differed significantly between groups; but later (days 5–7), the gabapentin group had superior scores for these measures. Gabapentin was also associated with significantly less sedation than chlordiazepoxide and trended to less alcohol craving.

Data suggest that gabapentin offers benefits for managing mild alcohol withdrawal. Improved residual craving and sleep measures are clinically important because they are risk factors for relapse. Mood and anxiety also improve with gabapentin, further indicating a therapeutic effect.

Gabapentin’s benefits for moderate and severe alcohol withdrawal have not been established. Seizures occurred during withdrawal despite gabapentin treatment, but whether from an insufficient dose, patient susceptibility, or lack of gabapentin efficacy is not clear. Best results occurred at the 1,200-mg daily dose, but benefits may not apply to patients with severe withdrawal. In addition, many studies were small, limiting the strength of conclusions.

Across most studies of gabapentin for alcohol withdrawal, advantages included a smoother transition into early abstinence due to improved sleep, mood, and anxiety, alleviating common triggers for a return to drinking. Gabapentin also carries less reinforcing potential than benzodiazepines. These qualities fueled interest in trying gabapentin to improve long-term abstinence.

GABAPENTIN FOR RELAPSE PREVENTION

Although naltrexone and acamprosate are the first-line treatments for relapse prevention, they do not help all patients and are more effective when combined with cognitive behavioral therapy.^1,29,30 For patients in whom standard treatments are not effective or tolerated, gabapentin may provide a reasonable alternative, and several randomized controlled trials have examined its use for this role.

Gabapentin alone is better than placebo

Furieri and Nakamura-Palacios⁴ assessed the use of gabapentin for relapse prevention in Brazilian outpatients (N = 60) who had averaged 27 years of drinking and consumed 17 drinks daily for the 90 days before baseline. After detoxification with diazepam and vitamins, patients were randomized to either gabapentin 300 mg twice daily or placebo for 4 weeks.

Compared with placebo, gabapentin significantly reduced cravings and lowered the percentage of heavy drinking days and the number of drinks per day, with a significant increase in the percentage of abstinent days. These self-reported measures correlated with decreases in gamma-glutamyl transferase, a biological marker for heavy drinking.

Brower et al³¹ investigated the use of gabapentin in 21 outpatients with AUD and insomnia who desired to remain abstinent. They were randomized to gabapentin (up to 1,500 mg at night) or placebo for 6 weeks. Just 14 participants completed the study; all but 2 were followed without treatment until week 12.

Gabapentin was associated with significantly lower relapse rates at 6 weeks (3 of 10 in the gabapentin group vs 9 of 11 in the placebo group) and at 12 weeks (6 of 10 in the gabapentin group vs 11 of 11 in the placebo group, assuming the 2 patients lost to follow-up relapsed). No difference between groups was detected for sleep measures in this small study. However, other studies have found that gabapentin for AUD improves measures of insomnia and daytime drowsiness—predictors of relapse—compared with other medications.¹⁶

High-dose gabapentin is better

Mason et al² randomized 150 outpatients with alcohol dependence to 12 weeks of daily treatment with either gabapentin (900 mg or 1,800 mg) or placebo after at least 3 days of abstinence. All participants received counseling. Drinking quantity and frequency were assessed by gamma-glutamyl transferase testing.

Patients taking gabapentin had better rates of abstinence and cessation of heavy drinking than those taking placebo. During the 12-week study, the 1,800-mg daily dose showed a substantially higher abstinence rate (17%) than either 900 mg  (11%) or placebo (4%). Significant dose-related improvements were also found for heavy drinking days, total drinking quantity, and frequency of alcohol withdrawal symptoms that predispose to early relapse, such as poor sleep, cravings, and poor mood. There were also significant linear dose effects on rates of abstinence and nondrinking days at the 24-week posttreatment follow-up.

Gabapentin plus naltrexone is better than naltrexone alone

Anton et al⁵ examined the efficacy of gabapentin combined with naltrexone during early abstinence. The study randomly assigned 150 people with AUD to one of the following groups:

• 16 weeks of naltrexone (50 mg/day) alone
• 6 weeks of naltrexone (50 mg/day) plus gabapentin (up to 1,200 mg/day), followed by 10 weeks of naltrexone alone
• Placebo.

All participants received medical management.

Over the first 6 weeks, those receiving naltrexone plus gabapentin had a longer interval to heavy drinking than those taking only naltrexone. By week 6, about half of those taking placebo or naltrexone alone had a heavy drinking day, compared with about 35% of those taking naltrexone plus gabapentin. Those receiving the combination also had fewer days of heavy drinking, fewer drinks per drinking day, and better sleep than the other groups. Participants in the naltrexone-alone group were more likely to drink heavily during periods in which they reported poor sleep. No significant group differences were found in measures of mood.

Gabapentin enacarbil is no better than placebo

Falk et al,³² in a 2019 preliminary analysis, examined data from a trial of gabapentin enacarbil, a prodrug formulation of gabapentin. In this 6-month double-blind study, 346 people with moderate AUD at 10 sites were randomized to gabapentin enacarbil extended-release 600 mg twice a day or placebo. All subjects received a computerized behavioral intervention.

No significant differences between groups were found in drinking measures or alcohol cravings, sleep problems, depression, or anxiety symptoms. However, a dose-response analysis found significantly less drinking for higher doses of the drug.

Bottom line: Evidence of benefits mixed but risk low

The efficacy of gabapentin as a treatment for AUD has varied across studies as a function of dosing and formulation. Daily doses have ranged from 600 mg to 1,800 mg, with the highest dose showing advantages in one study for cravings, insomnia, anxiety, dysphoria, and relapse.² Thus far, gabapentin immediate-release has performed better than gabapentin enacarbil extended-release. All forms of gabapentin have been well-tolerated in AUD trials.

The 2018 American Psychiatric Association guidelines stated that gabapentin had a small positive effect on drinking outcomes, but the harm of treatment was deemed minimal, especially relative to the harms of chronic drinking.³³ The guidelines endorse the use of gabapentin in patients with moderate to severe AUD who select gabapentin from the available options, or for those who are nonresponsive to or cannot tolerate naltrexone or acamprosate, as long as no contraindications exist. It was also noted that even small effects may be clinically important, considering the significant morbidity associated with AUD.

The use of gabapentin has become controversial owing to the growing recognition that it may not be as benign as initially thought.^7–9,34 A review of US legislative actions reflects concerns about its misuse.³⁵ In July 2017, Kentucky classified it as a schedule V controlled substance with prescription drug monitoring,³⁵ as did Tennessee in 2018³⁶ and Michigan in January 2019.³⁷ Currently, 8 other states (Massachusetts, Minnesota, Nebraska, North Dakota, Ohio, Virginia, Wyoming, and West Virginia) require prescription drug monitoring of gabapentin, and other states are considering it.³⁵

Efforts to understand gabapentin misuse derive largely from people with drug use disorders. A review of postmortem toxicology reports in fatal drug overdoses found gabapentin present in 22%.³⁸ Although it was not necessarily a cause of death, its high rate of detection suggests wide misuse among drug users.

Among a cohort of 503 prescription opioid misusers in Appalachian Kentucky, 15% reported using gabapentin “to get high.” Those who reported misusing gabapentin were 6 times more likely than nonusers to be abusing opioids and benzodiazepines. The main sources of gabapentin were doctors (52%) and dealers (36%). The average cost of gabapentin on the street was less than $1.00 per pill.³⁹

Gabapentin misuse by methadone clinic patients is also reported. Baird et al⁴⁰ surveyed patients in 6 addiction clinics in the United Kingdom for gabapentin and pregabalin abuse and found that 22% disclosed misusing these medications. Of these, 38% said they did so to enhance the methadone high.

In a review article, Quintero⁴¹ also cited enhancement of methadone euphoria and treatment of opioid withdrawal as motivations for misuse. Opioid-dependent gabapentin misusers consumed doses of gabapentin 3 to 20 times higher than clinically recommended and in combination with multiple drugs.⁴ Such use can cause dissociative and psychedelic effects.

Gabapentin also potentiates the sedative effects of opioids, thus increasing the risk of falls, accidents, and other adverse events.^34,35 Risk of opioid-related deaths was increased with coprescription of gabapentin and with moderate to high gabapentin doses.³⁴

Are people with AUD at higher risk of gabapentin abuse?

Despite concerns, patients in clinical trials of gabapentin treatment for AUD were not identified as at high risk for misuse of the drug.^2,4,5,16 Further, no such trials reported serious drug-related adverse events resulting in gabapentin discontinuation or side effects that differed from placebo in frequency or severity.^2,4,5,16

Clinical laboratory studies also have found no significant interactions between alcohol and gabapentin.^42,43 In fact, they showed no influence of gabapentin on the pharmacokinetics of alcohol or on alcohol’s subjective effects. Relative to placebo, gabapentin did not affect blood alcohol levels, the degree of intoxication, sedation, craving, or alcohol self-administration.

Smith et al⁹ reported estimates that only 1% of the general population misuse gabapentin. Another review concluded that gabapentin is seldom a drug of choice.¹⁷ Most patients prescribed gabapentin do not experience cravings or loss of control, which are hallmarks of addiction. Hence, with adequate precautions, the off-label use of gabapentin for AUD is reasonable.

CLINICAL IMPLICATIONS OF GABAPENTIN PRESCRIBING

Overall, evidence for the benefit of gabapentin in AUD is mixed. Subgroups of alcoholic patients, such as those who do not respond to or tolerate standard therapies, may particularly benefit, as may those with comorbid insomnia or neuropathic pain.⁴⁴ Clinicians should prescribe gabapentin only when it is likely to be helpful and should carefully document its efficacy.^2,45

At each visit, an open and honest assessment of the benefits and risks serves to promote shared decision-making regarding initiating, continuing, or discontinuing gabapentin.

For alcohol withdrawal

Before gabapentin is prescribed for alcohol withdrawal, potential benefits (reduction of withdrawal symptoms), side effects (sedation, fatigue), and risks (falls) should be discussed with the patient.⁴⁶ Patients should also be informed that benzodiazepines are the gold standard for alcohol withdrawal and that gabapentin is not effective for severe withdrawal.⁴⁶

For relapse prevention

When initiating treatment for relapse prevention, the patient and the prescriber should agree on specific goals (eg, reduction of drinking, anxiety, and insomnia).^2,16 Ongoing monitoring is essential and includes assessing and documenting improvement with respect to these goals.

In the AUD studies, gabapentin was well tolerated.¹⁶ Frequently observed side effects including headache, insomnia, fatigue, muscle aches, and gastrointestinal distress did not occur at a statistically different rate from placebo. However, patients in studies are selected samples, and their experience may not be generalizable to clinical practice. Thus, it is necessary to exercise caution and check for comorbidities that may put patients at risk of complications.⁴⁷ Older patients and those on hemodialysis are more susceptible to gabapentin side effects such as sedation, dizziness, ataxia, and mental status changes,³⁴ and prescribers should be alert for signs of toxicity (eg, ataxia, mental status changes).^47,48

Gabapentin misuse was not observed in AUD studies,^2,4,5,16 but evidence indicates that patients with opioid use disorder, prisoners, and polydrug users are at high risk for gabapentin misuse.^39–41 In all cases, clinicians should monitor for red flags that may indicate abuse, such as missed appointments, early refill requests, demands for increased dosage, and simultaneous opiate and benzodiazepine use.⁴⁹

Acknowledgment: The authors wish to thank Nick Mulligan for his invaluable assistance with formatting and grammar.

Perceptions regarding the use of gabapentin for alcohol use disorder (AUD) have shifted over time.^1–4 Early on, the drug was deemed to be benign and effective.^4–6 But more and more, concerns are being raised about its recreational use to achieve euphoria,⁷ and the drug is often misused by vulnerable populations, particularly those with opioid use disorder.^7–9

Given the large number of gabapentin prescriptions written off-label for AUD, it is incumbent on providers to understand how to prescribe it responsibly.^7–9 To that end, this article focuses on the benefits—and concerns—of this treatment option. We describe the effects of gabapentin on the central nervous system and how it may mitigate alcohol withdrawal and increase the likelihood of abstinence. In addition, we review clinical trials that evaluated potential roles of gabapentin in AUD, discuss the drug’s misuse potential, and suggest a framework for its appropriate use in AUD management.

ALCOHOL USE DISORDER IS COMMON AND SERIOUS

AUD affects about 14% of US adults and represents a significant health burden,¹ often with severe clinical and social implications. It manifests as compulsive drinking and loss of control despite adverse consequences on various life domains.¹⁰ It is generally associated with cravings, tolerance, and withdrawal symptoms upon cessation. Alcohol withdrawal is characterized by tremors, anxiety, sweating, nausea, and tachycardia, and in severe cases, may involve hallucinations, seizures, and delirium tremens. Untreated, alcohol withdrawal can be fatal.¹⁰

Even though psychosocial treatments for AUD by themselves are associated with high relapse rates, pharmacotherapy is underutilized. Three drugs approved by the US Food and Drug Administration (FDA) are available to treat it, but they are often poorly accepted and have limited efficacy. For these reasons, there is considerable interest in finding alternatives. Gabapentin is one of several agents that have been studied (Table 1). The topic has been reviewed in depth by Soyka and Müller.¹¹

GABAPENTIN REDUCES EXCITATION

The anticonvulsant gabapentin is FDA-approved for treating epilepsy, postherpetic neuralgia, and restless leg syndrome.^8,12–14 It binds and selectively impedes voltage-sensitive calcium channels, the pores in cell membrane that permit calcium to enter a neuron in response to changes in electrical currents.¹⁵

Gabapentin is believed to decrease excitation of the central nervous system in multiple ways:

• It reduces the release of glutamate, a key component of the excitatory system¹⁶
• It increases the concentration of gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the brain7
• By binding the alpha-2-delta type 1 subunit of voltage-sensitive calcium channels,^8,15–17 it inhibits excitatory synapse formation independent of calcium channel activity¹⁶
• By blocking excitatory neurotransmission, it also may indirectly increase the concentration of GABA in the central nervous system1^6,17
• It modulates action of glutamic acid decarboxylase (involved in the synthesis of GABA) and glutamate synthesizing enzyme to increase GABA and decrease glutamate.¹⁷

The actions of alcohol on the brain are also complex.¹⁸ Alpha-2-delta type 1 subunits of calcium channels are upregulated in the reward centers of the brain by addictive substances, including alcohol.¹⁶ Alcohol interacts with corticotropin-releasing factor and several neurotransmitters,¹⁸ and specifically affects neuropathways involving norepinephrine, GABA, and glutamate.¹⁹ Alcohol has reinforcing effects mediated by the release of dopamine in the nucleus accumbens.²⁰

Acutely, alcohol promotes GABA release and may also reduce GABA degradation, producing sedative and anxiolytic effects.²¹ Chronic alcohol use leads to a decrease in the number of GABAA receptors. Clinically, this downregulation manifests as tolerance to alcohol’s sedating effects.²¹

Alcohol affects the signaling of glutamatergic interaction with the N-methyl-d-aspartate (NMDA) receptor.²² Glutamate activates this receptor as well as the voltage-gated ion channels, modifying calcium influx and increasing neuronal excitability.^22,23 Acutely, alcohol has an antagonistic effect on the NMDA receptor, while chronic drinking upregulates (increases) the number of NMDA receptors and voltage-gated calcium channels.^22,23

Alcohol withdrawal increases excitatory effects

Patients experiencing alcohol withdrawal have decreased GABA-ergic functioning and increased glutamatergic action throughout the central nervous system.^19,24

Withdrawal can be subdivided into an acute phase (lasting up to about 5 days) and a protracted phase (of undetermined duration). During withdrawal, the brain activates its “stress system,” leading to overexpression of corticotropin-releasing factor in the amygdala. Protracted withdrawal dysregulates the prefrontal cortex, increasing cravings and worsening negative emotional states and sleep.¹⁶

GABAPENTIN FOR ALCOHOL WITHDRAWAL

Benzodiazepines are the standard treatment for alcohol withdrawal.^3,24 They relieve symptoms and can prevent seizures and delirium tremens,²⁴ but they are sedating and cause psychomotor impairments.³ Because of the potential for addiction, benzodiazepine use is limited to acute alcohol withdrawal.³

Gabapentin shows promise as an agent that can be used in withdrawal and continued through early abstinence without the highly addictive potential of benzodiazepines.¹⁶ It is thought to affect drinking behaviors during early abstinence by normalizing GABA and glutamate activity.^2,16

Early preclinical studies in mouse models found that gabapentin decreases anxiogenic and epileptic effects of alcohol withdrawal. Compared with other antidrinking medications, gabapentin has the benefits of lacking elimination via hepatic metabolism, few pharmacokinetic interactions, and good reported tolerability in this population.

Inpatient trials show no benefit over standard treatments

Bonnet et al²⁵ conducted a double-blind placebo-controlled trial in Germany in inpatients experiencing acute alcohol withdrawal to determine whether gabapentin might be an effective adjunct to clomethiazole, a GABAA modulator commonly used in Europe for alcohol withdrawal. Participants (N = 61) were randomized to receive placebo or gabapentin (400 mg every 6 hours) for 72 hours, with tapering over the next 3 days. All patients could receive rescue doses of clomethiazole, using a symptom-triggered protocol.

The study revealed no differences in the amount of clomethiazole administered between the 2 groups, suggesting that gabapentin had no adjunctive effect. Side effects (vertigo, nausea, dizziness, and ataxia) were mild and comparable between groups.

Nichols et al²⁶ conducted a retrospective cohort study in a South Carolina academic psychiatric hospital to assess the adjunctive effect of gabapentin on the as-needed use of benzodiazepines for alcohol withdrawal. The active group (n = 40) received gabapentin as well as a symptom-triggered alcohol withdrawal protocol of benzodiazepine. The control group (n = 43) received only the symptom-triggered alcohol withdrawal protocol without gabapentin.

No effect was found of gabapentin use for benzodiazepine treatment of alcohol withdrawal. It is notable that Bonnet et al and Nichols et al had similar findings despite their studies being conducted in different countries using distinct comparators and methods.

Bonnet et al,²⁷ in another study, tried a different design to investigate a possible role for gabapentin in inpatient alcohol withdrawal. The study included 37 patients with severe alcohol withdrawal (Clinical Institute Withdrawal Assessment of Alcohol Scale, Revised [CIWA-Ar] > 15).

All participants received gabapentin 800 mg. Those whose CIWA-Ar score improved within 2 hours were considered “early responders” (n = 27) and next received 2 days of gabapentin 600 mg 4 times a day before starting a taper. The nonresponders whose CIWA-Ar score worsened (associated with greater anxiety and depressive symptoms; n = 10) were switched to standard treatment with clomethiazole (n = 4) or clonazepam (n = 6). Scores of 3 early responders subsequently worsened; 2 of these participants developed seizures and were switched to standard treatment.

The authors concluded that gabapentin in a dose of 3,200 mg in the first 24 hours is useful only for milder forms of alcohol withdrawal. Hence, subsequent efforts on the use of gabapentin for alcohol withdrawal have focused on outpatients.

Outpatient trials reveal benefits over benzodiazepines

Myrick et al³ compared gabapentin vs lorazepam in 100 outpatients seeking treatment for alcohol withdrawal. Participants were randomized to 1 of 4 groups: gabapentin 600 mg, 900 mg, or 1,200 mg, or lorazepam 6 mg, each tapering over 4 days. Alcohol withdrawal was measured by the CIWA-Ar score. Only 68 patients completed all follow-up appointments to day 12.

Gabapentin 600 mg was discontinued because of seizures in 2 patients, but it was generally well tolerated and was associated with diminished symptoms of alcohol withdrawal, especially at the 1,200 mg dose. The gabapentin groups experienced less anxiety and sedation and fewer cravings than the lorazepam group. Those treated with lorazepam fared worse for achieving early abstinence and were more likely to return to drinking when the intervention was discontinued. However, significant relapse by day 12 occurred in both groups.

The authors concluded that gabapentin was at least as effective as lorazepam in the outpatient treatment of alcohol withdrawal, with the 1,200-mg gabapentin dosage being more effective than 900 mg. At 1,200 mg, gabapentin was associated with better sleep, less anxiety, and better self-reported ability to work than lorazepam, and at the 900-mg dose it was associated with less depression than lorazepam.

Stock et al²⁸ conducted a randomized, double-blind study of gabapentin in acute alcohol withdrawal in 26 military veterans in an outpatient setting. Patients were ran­domized to one of the following:

• Gabapentin 1,200 mg orally for 3 days, followed by 900 mg, 600 mg, and 300 mg for 1 day each (n = 17)
• Chlordiazepoxide 100 mg orally for 3 days, followed by 75 mg, 50 mg, and 25 mg for 1 day each (n = 9).

Withdrawal scores improved similarly in both groups. Early on (days 1–4), neither cravings nor sleep differed significantly between groups; but later (days 5–7), the gabapentin group had superior scores for these measures. Gabapentin was also associated with significantly less sedation than chlordiazepoxide and trended to less alcohol craving.

Data suggest that gabapentin offers benefits for managing mild alcohol withdrawal. Improved residual craving and sleep measures are clinically important because they are risk factors for relapse. Mood and anxiety also improve with gabapentin, further indicating a therapeutic effect.

Gabapentin’s benefits for moderate and severe alcohol withdrawal have not been established. Seizures occurred during withdrawal despite gabapentin treatment, but whether from an insufficient dose, patient susceptibility, or lack of gabapentin efficacy is not clear. Best results occurred at the 1,200-mg daily dose, but benefits may not apply to patients with severe withdrawal. In addition, many studies were small, limiting the strength of conclusions.

Across most studies of gabapentin for alcohol withdrawal, advantages included a smoother transition into early abstinence due to improved sleep, mood, and anxiety, alleviating common triggers for a return to drinking. Gabapentin also carries less reinforcing potential than benzodiazepines. These qualities fueled interest in trying gabapentin to improve long-term abstinence.

GABAPENTIN FOR RELAPSE PREVENTION

Although naltrexone and acamprosate are the first-line treatments for relapse prevention, they do not help all patients and are more effective when combined with cognitive behavioral therapy.^1,29,30 For patients in whom standard treatments are not effective or tolerated, gabapentin may provide a reasonable alternative, and several randomized controlled trials have examined its use for this role.

Gabapentin alone is better than placebo

Furieri and Nakamura-Palacios⁴ assessed the use of gabapentin for relapse prevention in Brazilian outpatients (N = 60) who had averaged 27 years of drinking and consumed 17 drinks daily for the 90 days before baseline. After detoxification with diazepam and vitamins, patients were randomized to either gabapentin 300 mg twice daily or placebo for 4 weeks.

Compared with placebo, gabapentin significantly reduced cravings and lowered the percentage of heavy drinking days and the number of drinks per day, with a significant increase in the percentage of abstinent days. These self-reported measures correlated with decreases in gamma-glutamyl transferase, a biological marker for heavy drinking.

Brower et al³¹ investigated the use of gabapentin in 21 outpatients with AUD and insomnia who desired to remain abstinent. They were randomized to gabapentin (up to 1,500 mg at night) or placebo for 6 weeks. Just 14 participants completed the study; all but 2 were followed without treatment until week 12.

Gabapentin was associated with significantly lower relapse rates at 6 weeks (3 of 10 in the gabapentin group vs 9 of 11 in the placebo group) and at 12 weeks (6 of 10 in the gabapentin group vs 11 of 11 in the placebo group, assuming the 2 patients lost to follow-up relapsed). No difference between groups was detected for sleep measures in this small study. However, other studies have found that gabapentin for AUD improves measures of insomnia and daytime drowsiness—predictors of relapse—compared with other medications.¹⁶

High-dose gabapentin is better

Mason et al² randomized 150 outpatients with alcohol dependence to 12 weeks of daily treatment with either gabapentin (900 mg or 1,800 mg) or placebo after at least 3 days of abstinence. All participants received counseling. Drinking quantity and frequency were assessed by gamma-glutamyl transferase testing.

Patients taking gabapentin had better rates of abstinence and cessation of heavy drinking than those taking placebo. During the 12-week study, the 1,800-mg daily dose showed a substantially higher abstinence rate (17%) than either 900 mg  (11%) or placebo (4%). Significant dose-related improvements were also found for heavy drinking days, total drinking quantity, and frequency of alcohol withdrawal symptoms that predispose to early relapse, such as poor sleep, cravings, and poor mood. There were also significant linear dose effects on rates of abstinence and nondrinking days at the 24-week posttreatment follow-up.

Gabapentin plus naltrexone is better than naltrexone alone

Anton et al⁵ examined the efficacy of gabapentin combined with naltrexone during early abstinence. The study randomly assigned 150 people with AUD to one of the following groups:

• 16 weeks of naltrexone (50 mg/day) alone
• 6 weeks of naltrexone (50 mg/day) plus gabapentin (up to 1,200 mg/day), followed by 10 weeks of naltrexone alone
• Placebo.

All participants received medical management.

Over the first 6 weeks, those receiving naltrexone plus gabapentin had a longer interval to heavy drinking than those taking only naltrexone. By week 6, about half of those taking placebo or naltrexone alone had a heavy drinking day, compared with about 35% of those taking naltrexone plus gabapentin. Those receiving the combination also had fewer days of heavy drinking, fewer drinks per drinking day, and better sleep than the other groups. Participants in the naltrexone-alone group were more likely to drink heavily during periods in which they reported poor sleep. No significant group differences were found in measures of mood.

Gabapentin enacarbil is no better than placebo

Falk et al,³² in a 2019 preliminary analysis, examined data from a trial of gabapentin enacarbil, a prodrug formulation of gabapentin. In this 6-month double-blind study, 346 people with moderate AUD at 10 sites were randomized to gabapentin enacarbil extended-release 600 mg twice a day or placebo. All subjects received a computerized behavioral intervention.

No significant differences between groups were found in drinking measures or alcohol cravings, sleep problems, depression, or anxiety symptoms. However, a dose-response analysis found significantly less drinking for higher doses of the drug.

Bottom line: Evidence of benefits mixed but risk low

The efficacy of gabapentin as a treatment for AUD has varied across studies as a function of dosing and formulation. Daily doses have ranged from 600 mg to 1,800 mg, with the highest dose showing advantages in one study for cravings, insomnia, anxiety, dysphoria, and relapse.² Thus far, gabapentin immediate-release has performed better than gabapentin enacarbil extended-release. All forms of gabapentin have been well-tolerated in AUD trials.

The 2018 American Psychiatric Association guidelines stated that gabapentin had a small positive effect on drinking outcomes, but the harm of treatment was deemed minimal, especially relative to the harms of chronic drinking.³³ The guidelines endorse the use of gabapentin in patients with moderate to severe AUD who select gabapentin from the available options, or for those who are nonresponsive to or cannot tolerate naltrexone or acamprosate, as long as no contraindications exist. It was also noted that even small effects may be clinically important, considering the significant morbidity associated with AUD.

The use of gabapentin has become controversial owing to the growing recognition that it may not be as benign as initially thought.^7–9,34 A review of US legislative actions reflects concerns about its misuse.³⁵ In July 2017, Kentucky classified it as a schedule V controlled substance with prescription drug monitoring,³⁵ as did Tennessee in 2018³⁶ and Michigan in January 2019.³⁷ Currently, 8 other states (Massachusetts, Minnesota, Nebraska, North Dakota, Ohio, Virginia, Wyoming, and West Virginia) require prescription drug monitoring of gabapentin, and other states are considering it.³⁵

Efforts to understand gabapentin misuse derive largely from people with drug use disorders. A review of postmortem toxicology reports in fatal drug overdoses found gabapentin present in 22%.³⁸ Although it was not necessarily a cause of death, its high rate of detection suggests wide misuse among drug users.

Among a cohort of 503 prescription opioid misusers in Appalachian Kentucky, 15% reported using gabapentin “to get high.” Those who reported misusing gabapentin were 6 times more likely than nonusers to be abusing opioids and benzodiazepines. The main sources of gabapentin were doctors (52%) and dealers (36%). The average cost of gabapentin on the street was less than $1.00 per pill.³⁹

Gabapentin misuse by methadone clinic patients is also reported. Baird et al⁴⁰ surveyed patients in 6 addiction clinics in the United Kingdom for gabapentin and pregabalin abuse and found that 22% disclosed misusing these medications. Of these, 38% said they did so to enhance the methadone high.

In a review article, Quintero⁴¹ also cited enhancement of methadone euphoria and treatment of opioid withdrawal as motivations for misuse. Opioid-dependent gabapentin misusers consumed doses of gabapentin 3 to 20 times higher than clinically recommended and in combination with multiple drugs.⁴ Such use can cause dissociative and psychedelic effects.

Gabapentin also potentiates the sedative effects of opioids, thus increasing the risk of falls, accidents, and other adverse events.^34,35 Risk of opioid-related deaths was increased with coprescription of gabapentin and with moderate to high gabapentin doses.³⁴

Are people with AUD at higher risk of gabapentin abuse?

Despite concerns, patients in clinical trials of gabapentin treatment for AUD were not identified as at high risk for misuse of the drug.^2,4,5,16 Further, no such trials reported serious drug-related adverse events resulting in gabapentin discontinuation or side effects that differed from placebo in frequency or severity.^2,4,5,16

Clinical laboratory studies also have found no significant interactions between alcohol and gabapentin.^42,43 In fact, they showed no influence of gabapentin on the pharmacokinetics of alcohol or on alcohol’s subjective effects. Relative to placebo, gabapentin did not affect blood alcohol levels, the degree of intoxication, sedation, craving, or alcohol self-administration.

Smith et al⁹ reported estimates that only 1% of the general population misuse gabapentin. Another review concluded that gabapentin is seldom a drug of choice.¹⁷ Most patients prescribed gabapentin do not experience cravings or loss of control, which are hallmarks of addiction. Hence, with adequate precautions, the off-label use of gabapentin for AUD is reasonable.

CLINICAL IMPLICATIONS OF GABAPENTIN PRESCRIBING

Overall, evidence for the benefit of gabapentin in AUD is mixed. Subgroups of alcoholic patients, such as those who do not respond to or tolerate standard therapies, may particularly benefit, as may those with comorbid insomnia or neuropathic pain.⁴⁴ Clinicians should prescribe gabapentin only when it is likely to be helpful and should carefully document its efficacy.^2,45

At each visit, an open and honest assessment of the benefits and risks serves to promote shared decision-making regarding initiating, continuing, or discontinuing gabapentin.

For alcohol withdrawal

Before gabapentin is prescribed for alcohol withdrawal, potential benefits (reduction of withdrawal symptoms), side effects (sedation, fatigue), and risks (falls) should be discussed with the patient.⁴⁶ Patients should also be informed that benzodiazepines are the gold standard for alcohol withdrawal and that gabapentin is not effective for severe withdrawal.⁴⁶

For relapse prevention

When initiating treatment for relapse prevention, the patient and the prescriber should agree on specific goals (eg, reduction of drinking, anxiety, and insomnia).^2,16 Ongoing monitoring is essential and includes assessing and documenting improvement with respect to these goals.

In the AUD studies, gabapentin was well tolerated.¹⁶ Frequently observed side effects including headache, insomnia, fatigue, muscle aches, and gastrointestinal distress did not occur at a statistically different rate from placebo. However, patients in studies are selected samples, and their experience may not be generalizable to clinical practice. Thus, it is necessary to exercise caution and check for comorbidities that may put patients at risk of complications.⁴⁷ Older patients and those on hemodialysis are more susceptible to gabapentin side effects such as sedation, dizziness, ataxia, and mental status changes,³⁴ and prescribers should be alert for signs of toxicity (eg, ataxia, mental status changes).^47,48

Gabapentin misuse was not observed in AUD studies,^2,4,5,16 but evidence indicates that patients with opioid use disorder, prisoners, and polydrug users are at high risk for gabapentin misuse.^39–41 In all cases, clinicians should monitor for red flags that may indicate abuse, such as missed appointments, early refill requests, demands for increased dosage, and simultaneous opiate and benzodiazepine use.⁴⁹

Acknowledgment: The authors wish to thank Nick Mulligan for his invaluable assistance with formatting and grammar.

In no way do I minimize the value of the imprimatur of FDA approval stating a drug, after appropriate preclinical and clinical studies, is deemed safe and effective. Whatever the agency’s shortcomings, the story of thalidomide (a drug never approved by the FDA) gives credence to the value of having a robust approval process. Arguments will likely continue forever as to whether the agency errs on the side of being too permissive or too restrictive in its approval process.

Nonetheless, I believe there are valid clinical reasons why we should continue to prescribe FDA-approved medications for nonapproved indications. In my practice, I treat some conditions that are sufficiently uncommon or heterogeneous in expression that large-scale clinical trials are logistically hard to carry out or deemed financially unviable by the corporate sponsor, even though clinical experience has informed us of a reasonable likelihood of efficacy. Sometimes drugs have “failed” in clinical trials, but experience and post hoc subset analysis of data have indicated a likely positive response in certain patients.

Although a drug that has been FDA approved has passed significant safety testing, the patients exposed to the drug when it was evaluated for treating a certain disease may be strikingly different from patients who have a different disease—the age, sex, comorbidities, and coprescribed medications may all differ significantly in the population of patients with the “off-label” disorder. Hence, appropriate caution is warranted, and if relevant, this should be explained to patients before giving them the medication.

In this issue of the Journal, 2 papers address the use of medications in an “off-label” manner. Schneider and colleagues discuss several frequent clinical uses of tricyclic antidepressants for reasons other than depression, and Modesto-Lowe and colleagues review the more controversial use of gabapentin in patients with alcohol use disorder. The hoped-for benefits in both circumstances are symptomatic, and both benefits and side effects are dose-related in ways not necessarily coinciding with those in the FDA-labeled indications.

My experience in using tricyclics as adjunctive treatment for fibromyalgia is that patients are quite sensitive to some of the side effects of the drugs (eg, oral dryness and fatigue), even in low doses. Moreover, we should expect only modest benefits, which should be explicitly described to the patient: improved quality of sleep with resultant decreased fatigue (while we watch closely for worsened fatigue from too-high dosing) and a modest reduction in pain over time as part of a multimodality treatment plan. I often find that practitioners who are less familiar with the use of these medications in this setting tend to start at lowish (but higher than often tolerated) doses, have patients take the medication too close to bedtime (resulting in some morning hangover sensation), fail to discuss the timing and degree of expected pain relief, don’t titrate the dose over time, and are not aware of the different responses that patients may experience with different medications within the same class. As with all prescribed medications, the benefits and ill effects must be frequently assessed, and particularly with these medications, one must be willing to discontinue them if appropriate outcomes are not achieved.

“Off-label” should not imply off the table as a therapeutic option. But it is incumbent on us to devote sufficient time to explain to each patient the anticipated side effects and hoped-for benefits, particularly since in most cases, we and our patients cannot refer to the results of definitive phase 3 clinical trials or patient online information sites that are totally relevant, reliable, data supported, and FDA reviewed.

In no way do I minimize the value of the imprimatur of FDA approval stating a drug, after appropriate preclinical and clinical studies, is deemed safe and effective. Whatever the agency’s shortcomings, the story of thalidomide (a drug never approved by the FDA) gives credence to the value of having a robust approval process. Arguments will likely continue forever as to whether the agency errs on the side of being too permissive or too restrictive in its approval process.

Nonetheless, I believe there are valid clinical reasons why we should continue to prescribe FDA-approved medications for nonapproved indications. In my practice, I treat some conditions that are sufficiently uncommon or heterogeneous in expression that large-scale clinical trials are logistically hard to carry out or deemed financially unviable by the corporate sponsor, even though clinical experience has informed us of a reasonable likelihood of efficacy. Sometimes drugs have “failed” in clinical trials, but experience and post hoc subset analysis of data have indicated a likely positive response in certain patients.

Although a drug that has been FDA approved has passed significant safety testing, the patients exposed to the drug when it was evaluated for treating a certain disease may be strikingly different from patients who have a different disease—the age, sex, comorbidities, and coprescribed medications may all differ significantly in the population of patients with the “off-label” disorder. Hence, appropriate caution is warranted, and if relevant, this should be explained to patients before giving them the medication.

In this issue of the Journal, 2 papers address the use of medications in an “off-label” manner. Schneider and colleagues discuss several frequent clinical uses of tricyclic antidepressants for reasons other than depression, and Modesto-Lowe and colleagues review the more controversial use of gabapentin in patients with alcohol use disorder. The hoped-for benefits in both circumstances are symptomatic, and both benefits and side effects are dose-related in ways not necessarily coinciding with those in the FDA-labeled indications.

My experience in using tricyclics as adjunctive treatment for fibromyalgia is that patients are quite sensitive to some of the side effects of the drugs (eg, oral dryness and fatigue), even in low doses. Moreover, we should expect only modest benefits, which should be explicitly described to the patient: improved quality of sleep with resultant decreased fatigue (while we watch closely for worsened fatigue from too-high dosing) and a modest reduction in pain over time as part of a multimodality treatment plan. I often find that practitioners who are less familiar with the use of these medications in this setting tend to start at lowish (but higher than often tolerated) doses, have patients take the medication too close to bedtime (resulting in some morning hangover sensation), fail to discuss the timing and degree of expected pain relief, don’t titrate the dose over time, and are not aware of the different responses that patients may experience with different medications within the same class. As with all prescribed medications, the benefits and ill effects must be frequently assessed, and particularly with these medications, one must be willing to discontinue them if appropriate outcomes are not achieved.

“Off-label” should not imply off the table as a therapeutic option. But it is incumbent on us to devote sufficient time to explain to each patient the anticipated side effects and hoped-for benefits, particularly since in most cases, we and our patients cannot refer to the results of definitive phase 3 clinical trials or patient online information sites that are totally relevant, reliable, data supported, and FDA reviewed.

In no way do I minimize the value of the imprimatur of FDA approval stating a drug, after appropriate preclinical and clinical studies, is deemed safe and effective. Whatever the agency’s shortcomings, the story of thalidomide (a drug never approved by the FDA) gives credence to the value of having a robust approval process. Arguments will likely continue forever as to whether the agency errs on the side of being too permissive or too restrictive in its approval process.

Nonetheless, I believe there are valid clinical reasons why we should continue to prescribe FDA-approved medications for nonapproved indications. In my practice, I treat some conditions that are sufficiently uncommon or heterogeneous in expression that large-scale clinical trials are logistically hard to carry out or deemed financially unviable by the corporate sponsor, even though clinical experience has informed us of a reasonable likelihood of efficacy. Sometimes drugs have “failed” in clinical trials, but experience and post hoc subset analysis of data have indicated a likely positive response in certain patients.

Although a drug that has been FDA approved has passed significant safety testing, the patients exposed to the drug when it was evaluated for treating a certain disease may be strikingly different from patients who have a different disease—the age, sex, comorbidities, and coprescribed medications may all differ significantly in the population of patients with the “off-label” disorder. Hence, appropriate caution is warranted, and if relevant, this should be explained to patients before giving them the medication.

In this issue of the Journal, 2 papers address the use of medications in an “off-label” manner. Schneider and colleagues discuss several frequent clinical uses of tricyclic antidepressants for reasons other than depression, and Modesto-Lowe and colleagues review the more controversial use of gabapentin in patients with alcohol use disorder. The hoped-for benefits in both circumstances are symptomatic, and both benefits and side effects are dose-related in ways not necessarily coinciding with those in the FDA-labeled indications.

My experience in using tricyclics as adjunctive treatment for fibromyalgia is that patients are quite sensitive to some of the side effects of the drugs (eg, oral dryness and fatigue), even in low doses. Moreover, we should expect only modest benefits, which should be explicitly described to the patient: improved quality of sleep with resultant decreased fatigue (while we watch closely for worsened fatigue from too-high dosing) and a modest reduction in pain over time as part of a multimodality treatment plan. I often find that practitioners who are less familiar with the use of these medications in this setting tend to start at lowish (but higher than often tolerated) doses, have patients take the medication too close to bedtime (resulting in some morning hangover sensation), fail to discuss the timing and degree of expected pain relief, don’t titrate the dose over time, and are not aware of the different responses that patients may experience with different medications within the same class. As with all prescribed medications, the benefits and ill effects must be frequently assessed, and particularly with these medications, one must be willing to discontinue them if appropriate outcomes are not achieved.

“Off-label” should not imply off the table as a therapeutic option. But it is incumbent on us to devote sufficient time to explain to each patient the anticipated side effects and hoped-for benefits, particularly since in most cases, we and our patients cannot refer to the results of definitive phase 3 clinical trials or patient online information sites that are totally relevant, reliable, data supported, and FDA reviewed.

A 66-year-old man presented with burning pain and erythema over the left axilla, and pustules that had ruptured and crusted over. The rash also involved the right axilla, trunk, abdomen, and face.

He said the symptoms had developed 3 days after starting to use ciprofloxacin eye drops for eye redness and purulent discharge that had been diagnosed as bacterial conjunctivitis. He was taking no other new medications. He was afebrile.

The ciprofloxacin drops were stopped. The skin lesions were treated with emollients, topical steroids, and topical mupirocin. Improvement was noted 3 days into the hospitalization, as the lesions started to crust over and dry up and no new lesions were forming. The conjunctivitis improved with topical bacitracin ointment and prednisolone drops.

ACUTE GENERALIZED EXANTHEMATOUS PUSTULOSIS

The differential diagnosis of drug-related acute generalized exanthematous pustulosis includes Stevens-Johnson syndrome, pustular psoriasis, folliculitis, and varicella infection. The characteristic features of the rash and lesions and the temporal relationship between the start of ciprofloxacin eye drops and the development of symptoms, combined with rapid resolution of symptoms within days after discontinuing the drops, accompanied by skin biopsy study showing diffuse spongiosis with scattered eosinophils and a subcorneal pustule, confirmed the diagnosis of AGEP.

Key features of AGEP include numerous small, sterile, nonfollicular pustules on an erythematous background with associated fever and sometimes neutrophilia and eosinophilia.¹ It usually begins on the face or in the intertriginous areas and then spreads to the trunk and lower limbs with rare mucosal involvement.¹ It can be associated with viral infections, but most reported cases are related to drug reactions.²

Our patient’s case was unusual because AGEP triggered by topical medications is rarely reported, especially with ophthalmic medications.³ Drugs most commonly implicated are antibiotics including penicillins, sulfonamides, and quinolones, but other drugs such as terbinafine, diltiazem, and hydroxychloroquine have also been associated.²

AGEP may present with extensive skin desquamation, as in our patient, sometimes with bullae formation and skin sloughing manifesting as AGEP with overlapping toxic epidermal necrolysis.⁴

Diagnosis entails a careful review of medications, attention to lesion morphology, compatible disease course, and a high index of suspicion. Treatment is supportive and consists of stopping the offending agent, wound care, and antipyretics. Evidence for the use of steroids is weak.⁵

TAKE-HOME POINTS

AGEP should be considered in sudden-onset pustular desquamating erythematous rash related to use of a new medication. It is important to be aware that topical and ophthalmic medications are possible triggers. A thorough medication review should be done. Antibiotics are the most commonly implicated medications. An alternative medication should be tried. Treatment is supportive, as the condition is usually self-limiting once the offending medication is discontinued. Rarely, extensive desquamation and bullae formation may occur, which may be a manifestation of overlap features with toxic epidermal necrolysis.

A 66-year-old man presented with burning pain and erythema over the left axilla, and pustules that had ruptured and crusted over. The rash also involved the right axilla, trunk, abdomen, and face.

He said the symptoms had developed 3 days after starting to use ciprofloxacin eye drops for eye redness and purulent discharge that had been diagnosed as bacterial conjunctivitis. He was taking no other new medications. He was afebrile.

The ciprofloxacin drops were stopped. The skin lesions were treated with emollients, topical steroids, and topical mupirocin. Improvement was noted 3 days into the hospitalization, as the lesions started to crust over and dry up and no new lesions were forming. The conjunctivitis improved with topical bacitracin ointment and prednisolone drops.

ACUTE GENERALIZED EXANTHEMATOUS PUSTULOSIS

The differential diagnosis of drug-related acute generalized exanthematous pustulosis includes Stevens-Johnson syndrome, pustular psoriasis, folliculitis, and varicella infection. The characteristic features of the rash and lesions and the temporal relationship between the start of ciprofloxacin eye drops and the development of symptoms, combined with rapid resolution of symptoms within days after discontinuing the drops, accompanied by skin biopsy study showing diffuse spongiosis with scattered eosinophils and a subcorneal pustule, confirmed the diagnosis of AGEP.

Key features of AGEP include numerous small, sterile, nonfollicular pustules on an erythematous background with associated fever and sometimes neutrophilia and eosinophilia.¹ It usually begins on the face or in the intertriginous areas and then spreads to the trunk and lower limbs with rare mucosal involvement.¹ It can be associated with viral infections, but most reported cases are related to drug reactions.²

Our patient’s case was unusual because AGEP triggered by topical medications is rarely reported, especially with ophthalmic medications.³ Drugs most commonly implicated are antibiotics including penicillins, sulfonamides, and quinolones, but other drugs such as terbinafine, diltiazem, and hydroxychloroquine have also been associated.²

AGEP may present with extensive skin desquamation, as in our patient, sometimes with bullae formation and skin sloughing manifesting as AGEP with overlapping toxic epidermal necrolysis.⁴

Diagnosis entails a careful review of medications, attention to lesion morphology, compatible disease course, and a high index of suspicion. Treatment is supportive and consists of stopping the offending agent, wound care, and antipyretics. Evidence for the use of steroids is weak.⁵

TAKE-HOME POINTS

AGEP should be considered in sudden-onset pustular desquamating erythematous rash related to use of a new medication. It is important to be aware that topical and ophthalmic medications are possible triggers. A thorough medication review should be done. Antibiotics are the most commonly implicated medications. An alternative medication should be tried. Treatment is supportive, as the condition is usually self-limiting once the offending medication is discontinued. Rarely, extensive desquamation and bullae formation may occur, which may be a manifestation of overlap features with toxic epidermal necrolysis.

A 66-year-old man presented with burning pain and erythema over the left axilla, and pustules that had ruptured and crusted over. The rash also involved the right axilla, trunk, abdomen, and face.

He said the symptoms had developed 3 days after starting to use ciprofloxacin eye drops for eye redness and purulent discharge that had been diagnosed as bacterial conjunctivitis. He was taking no other new medications. He was afebrile.

The ciprofloxacin drops were stopped. The skin lesions were treated with emollients, topical steroids, and topical mupirocin. Improvement was noted 3 days into the hospitalization, as the lesions started to crust over and dry up and no new lesions were forming. The conjunctivitis improved with topical bacitracin ointment and prednisolone drops.

ACUTE GENERALIZED EXANTHEMATOUS PUSTULOSIS

The differential diagnosis of drug-related acute generalized exanthematous pustulosis includes Stevens-Johnson syndrome, pustular psoriasis, folliculitis, and varicella infection. The characteristic features of the rash and lesions and the temporal relationship between the start of ciprofloxacin eye drops and the development of symptoms, combined with rapid resolution of symptoms within days after discontinuing the drops, accompanied by skin biopsy study showing diffuse spongiosis with scattered eosinophils and a subcorneal pustule, confirmed the diagnosis of AGEP.

Key features of AGEP include numerous small, sterile, nonfollicular pustules on an erythematous background with associated fever and sometimes neutrophilia and eosinophilia.¹ It usually begins on the face or in the intertriginous areas and then spreads to the trunk and lower limbs with rare mucosal involvement.¹ It can be associated with viral infections, but most reported cases are related to drug reactions.²

Our patient’s case was unusual because AGEP triggered by topical medications is rarely reported, especially with ophthalmic medications.³ Drugs most commonly implicated are antibiotics including penicillins, sulfonamides, and quinolones, but other drugs such as terbinafine, diltiazem, and hydroxychloroquine have also been associated.²

AGEP may present with extensive skin desquamation, as in our patient, sometimes with bullae formation and skin sloughing manifesting as AGEP with overlapping toxic epidermal necrolysis.⁴

Diagnosis entails a careful review of medications, attention to lesion morphology, compatible disease course, and a high index of suspicion. Treatment is supportive and consists of stopping the offending agent, wound care, and antipyretics. Evidence for the use of steroids is weak.⁵

TAKE-HOME POINTS

AGEP should be considered in sudden-onset pustular desquamating erythematous rash related to use of a new medication. It is important to be aware that topical and ophthalmic medications are possible triggers. A thorough medication review should be done. Antibiotics are the most commonly implicated medications. An alternative medication should be tried. Treatment is supportive, as the condition is usually self-limiting once the offending medication is discontinued. Rarely, extensive desquamation and bullae formation may occur, which may be a manifestation of overlap features with toxic epidermal necrolysis.

Recently, the FDA issued “black-box” warnings, its most prominent drug safety statements, for esketamine,¹ which is indicated for treatment-resistant depression, and the Z-drugs, which are indicated for insomnia² (Table 1). A black-box warning also comes with brexanolone, which was recently approved for postpartum depression.³ While these newly issued warnings serve as a timely reminder of the importance of black-box warnings, older black-box warnings also cover large areas of psychiatric prescribing, including all medications indicated for treating psychosis or schizophrenia (increased mortality in patients with dementia), and all psychotropic medications with a depression indication (suicidality in younger people).

In this article, we help busy prescribers navigate the landscape of black-box warnings by providing a concise review of how to use them in clinical practice, and where to find information to keep up-to-date.

What are black-box warnings?

A black-box warning is a summary of the potential serious or life-threatening risks of a specific prescription medication. The black-box warning is formatted within a black border found at the top of the manufacturer’s prescribing information document (also known as the package insert or product label). Below the black-box warning, potential risks appear in descending order in sections titled “Contraindications,” “Warnings and Precautions,” and “Adverse Reactions.”⁴ The FDA issues black-box warnings either during drug development, to take effect upon approval of a new agent, or (more commonly) based on post-marketing safety information,⁵ which the FDA continuously gathers from reports by patients, clinicians, and industry.⁶ Federal law mandates the existence of black-box warnings, stating in part that, “special problems, particularly those that may lead to death or serious injury, may be required by the [FDA] to be placed in a prominently displayed box” (21 CFR 201.57(e)).

When is a black-box warning necessary?

The FDA issues a black-box warning based upon its judgment of the seriousness of the adverse effect. However, by definition, these risks do not inherently outweigh the benefits a medication may offer to certain patients. According to the FDA,⁷ black-box warnings are placed when:

• an adverse reaction so significant exists that this potential negative effect must be considered in risks and benefits when prescribing the medication
• a serious adverse reaction exists that can be prevented, or the risk reduced, by appropriate use of the medication
• the FDA has approved the medication with restrictions to ensure safe use.

Table 2 shows examples of scenarios where black-box warnings have been issued.⁸ Black-box warnings may be placed on an individual agent or on an entire class of medications. For example, both antipsychotics and antidepressants have class-wide warnings. Finally, black-box warnings are not static, and their content may change; in a study of black-box warnings issued from 2007 to 2015, 29% were entirely new, 32% were considered major updates to existing black-box warnings, and 40% were minor updates.⁵

Critiques of black-box warnings focus on the absence of published, formal criteria for instituting such warnings, the lack of a consistent approach in their content, and the infrequent inclusion of any information on the relative size of the risk.⁹ Suggestions for improvement include offering guidance on how to implement the black-box warnings in a patient-centered, shared decision-making model by adding evidence profiles and implementation guides.¹⁰ Less frequently considered, black-box warnings may be discontinued if new evidence demonstrates that the risk is lower than previously appreciated; however, similarly to their placement, no explicit criteria for the removal of black-box warnings have been made public.¹¹

When a medication poses an especially high safety risk, the FDA may require the manufacturer to implement a Risk Evaluation and Mitigation Strategy (REMS) program. These programs can describe specific steps to improve medication safety, known as elements to assure safe use (ETASU).⁴ A familiar example is the clozapine REMS. In order to reduce the risk of severe neutropenia, the clozapine REMS requires prescribers (and pharmacists) to complete specialized training (making up the ETASU). Surprisingly, not every medication with a REMS has a corresponding black-box warning¹²; more understandably, many medications with black-box warnings do not have an associated REMS, because their risks are evaluated to be manageable by an individual prescriber’s clinical judgment. Most recently, esketamine carries both a black-box warning and a REMS. The black-box warning focuses on adverse effects (Table 1), while the REMS focuses on specific steps used to lessen these risks, including requiring use of a patient enrollment and monitoring form, a fact sheet for patients, and health care setting and pharmacy enrollment forms.¹³

Continue to: Psychotropic medications and black-box warnings

Psychotropic medications and black-box warnings

Psychotropic medications have a large number of black-box warnings.¹⁴ Because it is difficult to find black-box warnings for multiple medications in one place, we have provided 2 convenient resources to address this gap: a concise summary guide (Table 3) and a more detailed database (Table 4, Table 5, Table 6, Table 7, and Table 8). In these Tables, the possible risk mitigations, off-label uses, and monitoring are not meant to be formal recommendations or endorsements but are for independent clinician consideration only.

The information in these Tables was drawn from publicly available data, primarily the Micromedex and FDA web sites (see Related Resources). Because this information changes over time, at the end of this article we suggest ways for clinicians to stay updated with black-box warnings and build on the information provided in this article. These tools can be useful for day-to-day clinical practice in addition to studying for professional examinations. The following are selected high-profile black-box warnings.

Antidepressants and suicide risk. As a class, antidepressants carry a black-box warning on suicide risk in patients age ≤24. Initially issued in 2005, this warning was extended in 2007 to indicate that depression itself is associated with an increased risk of suicide. This black-box warning is used for an entire class of medications as well as for a specific patient population (age ≤24). Moreover, it indicates that suicide rates in patients age >65 were lower among patients using antidepressants.

Among psychotropic medication black-box warnings, this warning has perhaps been the most controversial. For example, it has been suggested that this black-box warning may have inadvertently increased suicide rates by discouraging clinicians from prescribing antidepressants,¹⁵ although this also has been called into question.¹⁶ This black-box warning illustrates that the consequences of issuing black-box warnings can be very difficult to assess, which makes their clinical effects highly complex and challenging to evaluate.¹⁴

Antipsychotics and dementia-related psychosis. This warning was initially issued in 2005 for second-generation antipsychotics and extended to first-generation antipsychotics in 2008. Anti­psychotics as a class carry a black-box warning for increased risk of death in patients with dementia (major neuro­cognitive disorder). This warning extends to the recently approved antipsychotic pimavanserin, even though this agent’s proposed mechanism of action differs from that of other antipsychotics.¹⁷ However, it specifically allows for use in Parkinson’s disease psychosis, which is pimavanserin’s indication.¹⁸ In light of recent research suggesting pimavanserin is effective in dementia-related psychosis,¹⁹ it bears watching whether this agent becomes the first antipsychotic to have this warning removed.

Continue to: This class warning has...

This class warning has had widespread effects. For example, it has prompted less use of antipsychotics in nursing home facilities, as a result of stricter Centers for Medicare and Medicaid Services regulations²⁰; overall, there is some evidence that there has been reduced prescribing of antipsychotics in general.²¹ Additionally, this black-box warning is unusual in that it warns about a specific off-label indication, which is itself poorly supported by evidence.²¹ Concomitantly, few other treatment options are available for this clinical situation. These medications are often seen as the only option for patients with dementia complicated by severe behavioral disturbance, and thus this black-box warning reflects real-world practices.¹⁴

Varenicline and neuropsychiatric complications. The withdrawal of the black-box warning on potential neuropsychiatric complications of using varenicline for smoking cessation shows that black-box warnings are not static and can, though infrequently, be removed as more safety data accumulates.¹¹ As additional post-marketing information emerged on this risk, this black-box warning was reconsidered and withdrawn in 2016.²² Its withdrawal could potentially make clinicians more comfortable prescribing varenicline and in turn, help to reduce smoking rates.

How to use black-box warnings

To enhance their clinical practice, prescribers can use black-box warnings to inform safe prescribing practices, to guide shared decision-making, and to improve documentation of their treatment decisions.

Informing safe prescribing practices. A prescriber should be aware of the main safety concerns contained in a medication’s black-box warning; at the same time, these warnings are not meant to unduly limit use when crucial treatment is needed.¹⁴ In issuing a black-box warning, the FDA has clearly stated the priority and seriousness of its concern. These safety issues must be balanced against the medication’s utility for a given patient, at the prescriber’s clinical judgment.

Guiding shared decision-making. Clinicians are not required to disclose black-box warnings to patients, and there are no criteria that clearly define the role of these warnings in patient care. As is often noted, the FDA does not regulate the practice of medicine.⁶ However, given the seriousness of the potential adverse effects delineated by black-box warnings, it is reasonable for clinicians to have a solid grasp of black-box warnings for all medications they prescribe, and to be able to relate these warnings to patients, in appropriate language. This patient-centered discussion should include weighing the risks and benefits with the patient and educating the patient about the risks and strategies to mitigate those risks. This discussion can be augmented by patient handouts, which are often offered by pharmaceutical manufacturers, and by shared decision-making tools. A proactive discussion with patients and families about black-box warnings and other risks discussed in product labels can help reduce fears associated with taking medications and may improve adherence.

Continue to: Improving documentation of treatment decisions

Improving documentation of treatment decisions. Fluent knowledge of black-box warnings may help clinicians improve documentation of their treatment decisions, particularly the risks and benefits of their medication choices. Fluency with black-box warnings will help clinicians accurately document both their awareness of these risks, and how these risks informed their risk-benefit analysis in specific clinical situations.

Despite the clear importance the FDA places on black-box warnings, they are not often a topic of study in training or in postgraduate continuing education, and as a result, not all clinicians may be equally conversant with black-box warnings. While black-box warnings do change over time, many psychotropic medication black-box warnings are long-standing and well-established, and they evolve slowly enough to make mastering these warnings worthwhile in order to make the most informed clinical decisions for patient care.

Keeping up-to-date

There are practical and useful ways for busy clinicians to stay up-to-date with black-box warnings. Although these resources exist in multiple locations, together they provide convenient ways to keep current.

The FDA provides access to black-box warnings via its comprehensive database, DRUGS@FDA (https://www.accessdata.fda.gov/scripts/cder/daf/). Detailed information about REMS (and corresponding ETASU and other information related to REMS programs) is available at REMS@FDA (https://www.accessdata.fda.gov/scripts/cder/rems/index.cfm). Clinicians can make safety reports that may contribute to FDA decision-making on black-box warnings by contacting MedWatch (https://www.fda.gov/safety/medwatch-fda-safety-information-and-adverse-event-reporting-program), the FDA’s adverse events reporting system. MedWatch releases safety information reports, which can be followed on Twitter @FDAMedWatch. Note that FDA information generally is organized by specific drug, and not into categories, such as psychotropic medications.

BlackBoxRx (www.blackboxrx.com) is a subscription-based web service that some clinicians may have access to via facility or academic resources as part of a larger FormWeb software package. Individuals also can subscribe (currently, $89/year).

Continue to: Micromedex

Micromedex (www.micromedex.com), which is widely available through medical libraries, is a subscription-based web service that provides black-box warning information from a separate tab that is easily accessed in each drug’s information front page. There is also an alphabetical list of black-box warnings under a separate tab on the Micromedex landing page.

ePocrates (www.epocrates.com) is a subscription-based service that provides extensive drug information, including black-box warnings, in a convenient mobile app.

Bottom Line

Black-box warnings are the most prominent drug safety warnings issued by the FDA. Many psychotropic medications carry black-box warnings that are crucial to everyday psychiatric prescribing. A better understanding of blackbox warnings can enhance your clinical practice by informing safe prescribing practices, guiding shared decision-making, and improving documentation of your treatment decisions.

Related Resources

• US Food and Drug Administration. DRUGS@FDA: FDAapproved drug products. www.accessdata.fda.gov/scripts/cder/daf/.
• US Food and Drug Administration. Drug safety and availability. www.fda.gov/drugs/drug-safety-and-availability. Updated October 10, 2019.
• BlackBoxRx. www.blackboxrx.com. (Subscription required.)
• Mircromedex. www.micromedex.com. (Subscription required.)
• ePocrates. www.epocrates.com. (Subscription required.)

Drug Brand Names

Amitriptyline • Elavil, Vanatrip
Amoxatine • Strattera
Amoxapine • Asendin
Aripiprazole • Abilify
Asenapine • Saphris
Brexanolone • Zulresso
Brexpiprazole • Rexulti
Bupropion • Wellbutrin
Carbamazepine • Tegretol
Cariprazine • Vraylar
Chlorpromazine • Thorazine
Citalopram • Celexa
Clomipramine • Anafranil
Clozapine • Clozaril
Desipramine • Norpramin
Desvenlafaxine • Pristiq
Dexmethylphenidate • Focalin
Dextroamphetamine/amphetamine • Adderall
Disulfiram • Antabuse
Doxepin • Prudoxin, Silenor
Droperidol • Inapsine
Duloxetine • Cymbalta
Escitalopram • Lexapro
Esketamine • Spravato
Eszopiclone • Lunesta
Fluoxetine • Prozac
Fluphenazine • Prolixin
Fluvoxamine • Luvox
Haloperidol • Haldol
Iloperidone • Fanapt
Imipramine • Tofranil
Isocarboxazid • Marplan
Lamotrigine • Lamictal
Levomilnacipran • Fetzima
Levothyroxine • Synthroid
Linezolid • Zyvox
Lisdexamfetamine • Vyvanse
Lithium • Eskalith, Lithobid
Loxapine • Loxitane
Lurasidone • Latuda
Maprotiline • Ludiomil
Methadone • Dolophine, Methadose
Methylphenidate • Ritalin, Concerta
Midazolam • Versed
Milnacipran • Savella
Mirtazapine • Remeron
Naltrexone • Revia, Vivitrol
Nefazodone • Serzone
Nortriptyline • Aventyl, Pamelor
Olanzapine • Zyprexa
Paliperidone • Invega
Paroxetine • Paxil
Perphenazine • Trilafon
Phenelzine • Nardil
Pimavanserin • Nuplazid
Prochlorperazine • Compro
Protriptyline • Vivactil
Quetiapine • Seroquel
Risperidone • Risperdal
Selegiline • Emsam
Sertraline • Zoloft
Thioridazine • Mellaril
Thiothixene • Navane
Tranylcypromine • Parnate
Trazodone • Desyrel, Oleptro
Trifluoperazine • Stelazine
Trimipramine • Surmontil
Valproate • Depakote
Varenicline • Chantix, Wellbutrin
Vilazodone • Viibryd
Venlafaxine • Effexor
Vortioxetine • Trintellix
Zaleplon • Sonata
Ziprasidone • Geodon
Zolpidem • Ambien

Recently, the FDA issued “black-box” warnings, its most prominent drug safety statements, for esketamine,¹ which is indicated for treatment-resistant depression, and the Z-drugs, which are indicated for insomnia² (Table 1). A black-box warning also comes with brexanolone, which was recently approved for postpartum depression.³ While these newly issued warnings serve as a timely reminder of the importance of black-box warnings, older black-box warnings also cover large areas of psychiatric prescribing, including all medications indicated for treating psychosis or schizophrenia (increased mortality in patients with dementia), and all psychotropic medications with a depression indication (suicidality in younger people).

In this article, we help busy prescribers navigate the landscape of black-box warnings by providing a concise review of how to use them in clinical practice, and where to find information to keep up-to-date.

What are black-box warnings?

A black-box warning is a summary of the potential serious or life-threatening risks of a specific prescription medication. The black-box warning is formatted within a black border found at the top of the manufacturer’s prescribing information document (also known as the package insert or product label). Below the black-box warning, potential risks appear in descending order in sections titled “Contraindications,” “Warnings and Precautions,” and “Adverse Reactions.”⁴ The FDA issues black-box warnings either during drug development, to take effect upon approval of a new agent, or (more commonly) based on post-marketing safety information,⁵ which the FDA continuously gathers from reports by patients, clinicians, and industry.⁶ Federal law mandates the existence of black-box warnings, stating in part that, “special problems, particularly those that may lead to death or serious injury, may be required by the [FDA] to be placed in a prominently displayed box” (21 CFR 201.57(e)).

When is a black-box warning necessary?

The FDA issues a black-box warning based upon its judgment of the seriousness of the adverse effect. However, by definition, these risks do not inherently outweigh the benefits a medication may offer to certain patients. According to the FDA,⁷ black-box warnings are placed when:

• an adverse reaction so significant exists that this potential negative effect must be considered in risks and benefits when prescribing the medication
• a serious adverse reaction exists that can be prevented, or the risk reduced, by appropriate use of the medication
• the FDA has approved the medication with restrictions to ensure safe use.

Table 2 shows examples of scenarios where black-box warnings have been issued.⁸ Black-box warnings may be placed on an individual agent or on an entire class of medications. For example, both antipsychotics and antidepressants have class-wide warnings. Finally, black-box warnings are not static, and their content may change; in a study of black-box warnings issued from 2007 to 2015, 29% were entirely new, 32% were considered major updates to existing black-box warnings, and 40% were minor updates.⁵

Critiques of black-box warnings focus on the absence of published, formal criteria for instituting such warnings, the lack of a consistent approach in their content, and the infrequent inclusion of any information on the relative size of the risk.⁹ Suggestions for improvement include offering guidance on how to implement the black-box warnings in a patient-centered, shared decision-making model by adding evidence profiles and implementation guides.¹⁰ Less frequently considered, black-box warnings may be discontinued if new evidence demonstrates that the risk is lower than previously appreciated; however, similarly to their placement, no explicit criteria for the removal of black-box warnings have been made public.¹¹

When a medication poses an especially high safety risk, the FDA may require the manufacturer to implement a Risk Evaluation and Mitigation Strategy (REMS) program. These programs can describe specific steps to improve medication safety, known as elements to assure safe use (ETASU).⁴ A familiar example is the clozapine REMS. In order to reduce the risk of severe neutropenia, the clozapine REMS requires prescribers (and pharmacists) to complete specialized training (making up the ETASU). Surprisingly, not every medication with a REMS has a corresponding black-box warning¹²; more understandably, many medications with black-box warnings do not have an associated REMS, because their risks are evaluated to be manageable by an individual prescriber’s clinical judgment. Most recently, esketamine carries both a black-box warning and a REMS. The black-box warning focuses on adverse effects (Table 1), while the REMS focuses on specific steps used to lessen these risks, including requiring use of a patient enrollment and monitoring form, a fact sheet for patients, and health care setting and pharmacy enrollment forms.¹³

Continue to: Psychotropic medications and black-box warnings

Psychotropic medications and black-box warnings

Psychotropic medications have a large number of black-box warnings.¹⁴ Because it is difficult to find black-box warnings for multiple medications in one place, we have provided 2 convenient resources to address this gap: a concise summary guide (Table 3) and a more detailed database (Table 4, Table 5, Table 6, Table 7, and Table 8). In these Tables, the possible risk mitigations, off-label uses, and monitoring are not meant to be formal recommendations or endorsements but are for independent clinician consideration only.

The information in these Tables was drawn from publicly available data, primarily the Micromedex and FDA web sites (see Related Resources). Because this information changes over time, at the end of this article we suggest ways for clinicians to stay updated with black-box warnings and build on the information provided in this article. These tools can be useful for day-to-day clinical practice in addition to studying for professional examinations. The following are selected high-profile black-box warnings.

Antidepressants and suicide risk. As a class, antidepressants carry a black-box warning on suicide risk in patients age ≤24. Initially issued in 2005, this warning was extended in 2007 to indicate that depression itself is associated with an increased risk of suicide. This black-box warning is used for an entire class of medications as well as for a specific patient population (age ≤24). Moreover, it indicates that suicide rates in patients age >65 were lower among patients using antidepressants.

Among psychotropic medication black-box warnings, this warning has perhaps been the most controversial. For example, it has been suggested that this black-box warning may have inadvertently increased suicide rates by discouraging clinicians from prescribing antidepressants,¹⁵ although this also has been called into question.¹⁶ This black-box warning illustrates that the consequences of issuing black-box warnings can be very difficult to assess, which makes their clinical effects highly complex and challenging to evaluate.¹⁴

Antipsychotics and dementia-related psychosis. This warning was initially issued in 2005 for second-generation antipsychotics and extended to first-generation antipsychotics in 2008. Anti­psychotics as a class carry a black-box warning for increased risk of death in patients with dementia (major neuro­cognitive disorder). This warning extends to the recently approved antipsychotic pimavanserin, even though this agent’s proposed mechanism of action differs from that of other antipsychotics.¹⁷ However, it specifically allows for use in Parkinson’s disease psychosis, which is pimavanserin’s indication.¹⁸ In light of recent research suggesting pimavanserin is effective in dementia-related psychosis,¹⁹ it bears watching whether this agent becomes the first antipsychotic to have this warning removed.

Continue to: This class warning has...

This class warning has had widespread effects. For example, it has prompted less use of antipsychotics in nursing home facilities, as a result of stricter Centers for Medicare and Medicaid Services regulations²⁰; overall, there is some evidence that there has been reduced prescribing of antipsychotics in general.²¹ Additionally, this black-box warning is unusual in that it warns about a specific off-label indication, which is itself poorly supported by evidence.²¹ Concomitantly, few other treatment options are available for this clinical situation. These medications are often seen as the only option for patients with dementia complicated by severe behavioral disturbance, and thus this black-box warning reflects real-world practices.¹⁴

Varenicline and neuropsychiatric complications. The withdrawal of the black-box warning on potential neuropsychiatric complications of using varenicline for smoking cessation shows that black-box warnings are not static and can, though infrequently, be removed as more safety data accumulates.¹¹ As additional post-marketing information emerged on this risk, this black-box warning was reconsidered and withdrawn in 2016.²² Its withdrawal could potentially make clinicians more comfortable prescribing varenicline and in turn, help to reduce smoking rates.

How to use black-box warnings

To enhance their clinical practice, prescribers can use black-box warnings to inform safe prescribing practices, to guide shared decision-making, and to improve documentation of their treatment decisions.

Informing safe prescribing practices. A prescriber should be aware of the main safety concerns contained in a medication’s black-box warning; at the same time, these warnings are not meant to unduly limit use when crucial treatment is needed.¹⁴ In issuing a black-box warning, the FDA has clearly stated the priority and seriousness of its concern. These safety issues must be balanced against the medication’s utility for a given patient, at the prescriber’s clinical judgment.

Guiding shared decision-making. Clinicians are not required to disclose black-box warnings to patients, and there are no criteria that clearly define the role of these warnings in patient care. As is often noted, the FDA does not regulate the practice of medicine.⁶ However, given the seriousness of the potential adverse effects delineated by black-box warnings, it is reasonable for clinicians to have a solid grasp of black-box warnings for all medications they prescribe, and to be able to relate these warnings to patients, in appropriate language. This patient-centered discussion should include weighing the risks and benefits with the patient and educating the patient about the risks and strategies to mitigate those risks. This discussion can be augmented by patient handouts, which are often offered by pharmaceutical manufacturers, and by shared decision-making tools. A proactive discussion with patients and families about black-box warnings and other risks discussed in product labels can help reduce fears associated with taking medications and may improve adherence.

Continue to: Improving documentation of treatment decisions

Improving documentation of treatment decisions. Fluent knowledge of black-box warnings may help clinicians improve documentation of their treatment decisions, particularly the risks and benefits of their medication choices. Fluency with black-box warnings will help clinicians accurately document both their awareness of these risks, and how these risks informed their risk-benefit analysis in specific clinical situations.

Despite the clear importance the FDA places on black-box warnings, they are not often a topic of study in training or in postgraduate continuing education, and as a result, not all clinicians may be equally conversant with black-box warnings. While black-box warnings do change over time, many psychotropic medication black-box warnings are long-standing and well-established, and they evolve slowly enough to make mastering these warnings worthwhile in order to make the most informed clinical decisions for patient care.

Keeping up-to-date

There are practical and useful ways for busy clinicians to stay up-to-date with black-box warnings. Although these resources exist in multiple locations, together they provide convenient ways to keep current.

The FDA provides access to black-box warnings via its comprehensive database, DRUGS@FDA (https://www.accessdata.fda.gov/scripts/cder/daf/). Detailed information about REMS (and corresponding ETASU and other information related to REMS programs) is available at REMS@FDA (https://www.accessdata.fda.gov/scripts/cder/rems/index.cfm). Clinicians can make safety reports that may contribute to FDA decision-making on black-box warnings by contacting MedWatch (https://www.fda.gov/safety/medwatch-fda-safety-information-and-adverse-event-reporting-program), the FDA’s adverse events reporting system. MedWatch releases safety information reports, which can be followed on Twitter @FDAMedWatch. Note that FDA information generally is organized by specific drug, and not into categories, such as psychotropic medications.

BlackBoxRx (www.blackboxrx.com) is a subscription-based web service that some clinicians may have access to via facility or academic resources as part of a larger FormWeb software package. Individuals also can subscribe (currently, $89/year).

Continue to: Micromedex

Micromedex (www.micromedex.com), which is widely available through medical libraries, is a subscription-based web service that provides black-box warning information from a separate tab that is easily accessed in each drug’s information front page. There is also an alphabetical list of black-box warnings under a separate tab on the Micromedex landing page.

ePocrates (www.epocrates.com) is a subscription-based service that provides extensive drug information, including black-box warnings, in a convenient mobile app.

Bottom Line

Black-box warnings are the most prominent drug safety warnings issued by the FDA. Many psychotropic medications carry black-box warnings that are crucial to everyday psychiatric prescribing. A better understanding of blackbox warnings can enhance your clinical practice by informing safe prescribing practices, guiding shared decision-making, and improving documentation of your treatment decisions.

Related Resources

• US Food and Drug Administration. DRUGS@FDA: FDAapproved drug products. www.accessdata.fda.gov/scripts/cder/daf/.
• US Food and Drug Administration. Drug safety and availability. www.fda.gov/drugs/drug-safety-and-availability. Updated October 10, 2019.
• BlackBoxRx. www.blackboxrx.com. (Subscription required.)
• Mircromedex. www.micromedex.com. (Subscription required.)
• ePocrates. www.epocrates.com. (Subscription required.)

Drug Brand Names

Amitriptyline • Elavil, Vanatrip
Amoxatine • Strattera
Amoxapine • Asendin
Aripiprazole • Abilify
Asenapine • Saphris
Brexanolone • Zulresso
Brexpiprazole • Rexulti
Bupropion • Wellbutrin
Carbamazepine • Tegretol
Cariprazine • Vraylar
Chlorpromazine • Thorazine
Citalopram • Celexa
Clomipramine • Anafranil
Clozapine • Clozaril
Desipramine • Norpramin
Desvenlafaxine • Pristiq
Dexmethylphenidate • Focalin
Dextroamphetamine/amphetamine • Adderall
Disulfiram • Antabuse
Doxepin • Prudoxin, Silenor
Droperidol • Inapsine
Duloxetine • Cymbalta
Escitalopram • Lexapro
Esketamine • Spravato
Eszopiclone • Lunesta
Fluoxetine • Prozac
Fluphenazine • Prolixin
Fluvoxamine • Luvox
Haloperidol • Haldol
Iloperidone • Fanapt
Imipramine • Tofranil
Isocarboxazid • Marplan
Lamotrigine • Lamictal
Levomilnacipran • Fetzima
Levothyroxine • Synthroid
Linezolid • Zyvox
Lisdexamfetamine • Vyvanse
Lithium • Eskalith, Lithobid
Loxapine • Loxitane
Lurasidone • Latuda
Maprotiline • Ludiomil
Methadone • Dolophine, Methadose
Methylphenidate • Ritalin, Concerta
Midazolam • Versed
Milnacipran • Savella
Mirtazapine • Remeron
Naltrexone • Revia, Vivitrol
Nefazodone • Serzone
Nortriptyline • Aventyl, Pamelor
Olanzapine • Zyprexa
Paliperidone • Invega
Paroxetine • Paxil
Perphenazine • Trilafon
Phenelzine • Nardil
Pimavanserin • Nuplazid
Prochlorperazine • Compro
Protriptyline • Vivactil
Quetiapine • Seroquel
Risperidone • Risperdal
Selegiline • Emsam
Sertraline • Zoloft
Thioridazine • Mellaril
Thiothixene • Navane
Tranylcypromine • Parnate
Trazodone • Desyrel, Oleptro
Trifluoperazine • Stelazine
Trimipramine • Surmontil
Valproate • Depakote
Varenicline • Chantix, Wellbutrin
Vilazodone • Viibryd
Venlafaxine • Effexor
Vortioxetine • Trintellix
Zaleplon • Sonata
Ziprasidone • Geodon
Zolpidem • Ambien

Recently, the FDA issued “black-box” warnings, its most prominent drug safety statements, for esketamine,¹ which is indicated for treatment-resistant depression, and the Z-drugs, which are indicated for insomnia² (Table 1). A black-box warning also comes with brexanolone, which was recently approved for postpartum depression.³ While these newly issued warnings serve as a timely reminder of the importance of black-box warnings, older black-box warnings also cover large areas of psychiatric prescribing, including all medications indicated for treating psychosis or schizophrenia (increased mortality in patients with dementia), and all psychotropic medications with a depression indication (suicidality in younger people).

In this article, we help busy prescribers navigate the landscape of black-box warnings by providing a concise review of how to use them in clinical practice, and where to find information to keep up-to-date.

What are black-box warnings?

A black-box warning is a summary of the potential serious or life-threatening risks of a specific prescription medication. The black-box warning is formatted within a black border found at the top of the manufacturer’s prescribing information document (also known as the package insert or product label). Below the black-box warning, potential risks appear in descending order in sections titled “Contraindications,” “Warnings and Precautions,” and “Adverse Reactions.”⁴ The FDA issues black-box warnings either during drug development, to take effect upon approval of a new agent, or (more commonly) based on post-marketing safety information,⁵ which the FDA continuously gathers from reports by patients, clinicians, and industry.⁶ Federal law mandates the existence of black-box warnings, stating in part that, “special problems, particularly those that may lead to death or serious injury, may be required by the [FDA] to be placed in a prominently displayed box” (21 CFR 201.57(e)).

When is a black-box warning necessary?

The FDA issues a black-box warning based upon its judgment of the seriousness of the adverse effect. However, by definition, these risks do not inherently outweigh the benefits a medication may offer to certain patients. According to the FDA,⁷ black-box warnings are placed when:

• an adverse reaction so significant exists that this potential negative effect must be considered in risks and benefits when prescribing the medication
• a serious adverse reaction exists that can be prevented, or the risk reduced, by appropriate use of the medication
• the FDA has approved the medication with restrictions to ensure safe use.

Table 2 shows examples of scenarios where black-box warnings have been issued.⁸ Black-box warnings may be placed on an individual agent or on an entire class of medications. For example, both antipsychotics and antidepressants have class-wide warnings. Finally, black-box warnings are not static, and their content may change; in a study of black-box warnings issued from 2007 to 2015, 29% were entirely new, 32% were considered major updates to existing black-box warnings, and 40% were minor updates.⁵

Critiques of black-box warnings focus on the absence of published, formal criteria for instituting such warnings, the lack of a consistent approach in their content, and the infrequent inclusion of any information on the relative size of the risk.⁹ Suggestions for improvement include offering guidance on how to implement the black-box warnings in a patient-centered, shared decision-making model by adding evidence profiles and implementation guides.¹⁰ Less frequently considered, black-box warnings may be discontinued if new evidence demonstrates that the risk is lower than previously appreciated; however, similarly to their placement, no explicit criteria for the removal of black-box warnings have been made public.¹¹

When a medication poses an especially high safety risk, the FDA may require the manufacturer to implement a Risk Evaluation and Mitigation Strategy (REMS) program. These programs can describe specific steps to improve medication safety, known as elements to assure safe use (ETASU).⁴ A familiar example is the clozapine REMS. In order to reduce the risk of severe neutropenia, the clozapine REMS requires prescribers (and pharmacists) to complete specialized training (making up the ETASU). Surprisingly, not every medication with a REMS has a corresponding black-box warning¹²; more understandably, many medications with black-box warnings do not have an associated REMS, because their risks are evaluated to be manageable by an individual prescriber’s clinical judgment. Most recently, esketamine carries both a black-box warning and a REMS. The black-box warning focuses on adverse effects (Table 1), while the REMS focuses on specific steps used to lessen these risks, including requiring use of a patient enrollment and monitoring form, a fact sheet for patients, and health care setting and pharmacy enrollment forms.¹³

Continue to: Psychotropic medications and black-box warnings

Psychotropic medications and black-box warnings

Psychotropic medications have a large number of black-box warnings.¹⁴ Because it is difficult to find black-box warnings for multiple medications in one place, we have provided 2 convenient resources to address this gap: a concise summary guide (Table 3) and a more detailed database (Table 4, Table 5, Table 6, Table 7, and Table 8). In these Tables, the possible risk mitigations, off-label uses, and monitoring are not meant to be formal recommendations or endorsements but are for independent clinician consideration only.

The information in these Tables was drawn from publicly available data, primarily the Micromedex and FDA web sites (see Related Resources). Because this information changes over time, at the end of this article we suggest ways for clinicians to stay updated with black-box warnings and build on the information provided in this article. These tools can be useful for day-to-day clinical practice in addition to studying for professional examinations. The following are selected high-profile black-box warnings.

Antidepressants and suicide risk. As a class, antidepressants carry a black-box warning on suicide risk in patients age ≤24. Initially issued in 2005, this warning was extended in 2007 to indicate that depression itself is associated with an increased risk of suicide. This black-box warning is used for an entire class of medications as well as for a specific patient population (age ≤24). Moreover, it indicates that suicide rates in patients age >65 were lower among patients using antidepressants.

Among psychotropic medication black-box warnings, this warning has perhaps been the most controversial. For example, it has been suggested that this black-box warning may have inadvertently increased suicide rates by discouraging clinicians from prescribing antidepressants,¹⁵ although this also has been called into question.¹⁶ This black-box warning illustrates that the consequences of issuing black-box warnings can be very difficult to assess, which makes their clinical effects highly complex and challenging to evaluate.¹⁴

Antipsychotics and dementia-related psychosis. This warning was initially issued in 2005 for second-generation antipsychotics and extended to first-generation antipsychotics in 2008. Anti­psychotics as a class carry a black-box warning for increased risk of death in patients with dementia (major neuro­cognitive disorder). This warning extends to the recently approved antipsychotic pimavanserin, even though this agent’s proposed mechanism of action differs from that of other antipsychotics.¹⁷ However, it specifically allows for use in Parkinson’s disease psychosis, which is pimavanserin’s indication.¹⁸ In light of recent research suggesting pimavanserin is effective in dementia-related psychosis,¹⁹ it bears watching whether this agent becomes the first antipsychotic to have this warning removed.

Continue to: This class warning has...

This class warning has had widespread effects. For example, it has prompted less use of antipsychotics in nursing home facilities, as a result of stricter Centers for Medicare and Medicaid Services regulations²⁰; overall, there is some evidence that there has been reduced prescribing of antipsychotics in general.²¹ Additionally, this black-box warning is unusual in that it warns about a specific off-label indication, which is itself poorly supported by evidence.²¹ Concomitantly, few other treatment options are available for this clinical situation. These medications are often seen as the only option for patients with dementia complicated by severe behavioral disturbance, and thus this black-box warning reflects real-world practices.¹⁴

Varenicline and neuropsychiatric complications. The withdrawal of the black-box warning on potential neuropsychiatric complications of using varenicline for smoking cessation shows that black-box warnings are not static and can, though infrequently, be removed as more safety data accumulates.¹¹ As additional post-marketing information emerged on this risk, this black-box warning was reconsidered and withdrawn in 2016.²² Its withdrawal could potentially make clinicians more comfortable prescribing varenicline and in turn, help to reduce smoking rates.

How to use black-box warnings

To enhance their clinical practice, prescribers can use black-box warnings to inform safe prescribing practices, to guide shared decision-making, and to improve documentation of their treatment decisions.

Informing safe prescribing practices. A prescriber should be aware of the main safety concerns contained in a medication’s black-box warning; at the same time, these warnings are not meant to unduly limit use when crucial treatment is needed.¹⁴ In issuing a black-box warning, the FDA has clearly stated the priority and seriousness of its concern. These safety issues must be balanced against the medication’s utility for a given patient, at the prescriber’s clinical judgment.

Guiding shared decision-making. Clinicians are not required to disclose black-box warnings to patients, and there are no criteria that clearly define the role of these warnings in patient care. As is often noted, the FDA does not regulate the practice of medicine.⁶ However, given the seriousness of the potential adverse effects delineated by black-box warnings, it is reasonable for clinicians to have a solid grasp of black-box warnings for all medications they prescribe, and to be able to relate these warnings to patients, in appropriate language. This patient-centered discussion should include weighing the risks and benefits with the patient and educating the patient about the risks and strategies to mitigate those risks. This discussion can be augmented by patient handouts, which are often offered by pharmaceutical manufacturers, and by shared decision-making tools. A proactive discussion with patients and families about black-box warnings and other risks discussed in product labels can help reduce fears associated with taking medications and may improve adherence.

Continue to: Improving documentation of treatment decisions

Improving documentation of treatment decisions. Fluent knowledge of black-box warnings may help clinicians improve documentation of their treatment decisions, particularly the risks and benefits of their medication choices. Fluency with black-box warnings will help clinicians accurately document both their awareness of these risks, and how these risks informed their risk-benefit analysis in specific clinical situations.

Despite the clear importance the FDA places on black-box warnings, they are not often a topic of study in training or in postgraduate continuing education, and as a result, not all clinicians may be equally conversant with black-box warnings. While black-box warnings do change over time, many psychotropic medication black-box warnings are long-standing and well-established, and they evolve slowly enough to make mastering these warnings worthwhile in order to make the most informed clinical decisions for patient care.

Keeping up-to-date

There are practical and useful ways for busy clinicians to stay up-to-date with black-box warnings. Although these resources exist in multiple locations, together they provide convenient ways to keep current.

The FDA provides access to black-box warnings via its comprehensive database, DRUGS@FDA (https://www.accessdata.fda.gov/scripts/cder/daf/). Detailed information about REMS (and corresponding ETASU and other information related to REMS programs) is available at REMS@FDA (https://www.accessdata.fda.gov/scripts/cder/rems/index.cfm). Clinicians can make safety reports that may contribute to FDA decision-making on black-box warnings by contacting MedWatch (https://www.fda.gov/safety/medwatch-fda-safety-information-and-adverse-event-reporting-program), the FDA’s adverse events reporting system. MedWatch releases safety information reports, which can be followed on Twitter @FDAMedWatch. Note that FDA information generally is organized by specific drug, and not into categories, such as psychotropic medications.

BlackBoxRx (www.blackboxrx.com) is a subscription-based web service that some clinicians may have access to via facility or academic resources as part of a larger FormWeb software package. Individuals also can subscribe (currently, $89/year).

Continue to: Micromedex

Micromedex (www.micromedex.com), which is widely available through medical libraries, is a subscription-based web service that provides black-box warning information from a separate tab that is easily accessed in each drug’s information front page. There is also an alphabetical list of black-box warnings under a separate tab on the Micromedex landing page.

ePocrates (www.epocrates.com) is a subscription-based service that provides extensive drug information, including black-box warnings, in a convenient mobile app.

Bottom Line

Black-box warnings are the most prominent drug safety warnings issued by the FDA. Many psychotropic medications carry black-box warnings that are crucial to everyday psychiatric prescribing. A better understanding of blackbox warnings can enhance your clinical practice by informing safe prescribing practices, guiding shared decision-making, and improving documentation of your treatment decisions.

Related Resources

• US Food and Drug Administration. DRUGS@FDA: FDAapproved drug products. www.accessdata.fda.gov/scripts/cder/daf/.
• US Food and Drug Administration. Drug safety and availability. www.fda.gov/drugs/drug-safety-and-availability. Updated October 10, 2019.
• BlackBoxRx. www.blackboxrx.com. (Subscription required.)
• Mircromedex. www.micromedex.com. (Subscription required.)
• ePocrates. www.epocrates.com. (Subscription required.)

Drug Brand Names

Amitriptyline • Elavil, Vanatrip
Amoxatine • Strattera
Amoxapine • Asendin
Aripiprazole • Abilify
Asenapine • Saphris
Brexanolone • Zulresso
Brexpiprazole • Rexulti
Bupropion • Wellbutrin
Carbamazepine • Tegretol
Cariprazine • Vraylar
Chlorpromazine • Thorazine
Citalopram • Celexa
Clomipramine • Anafranil
Clozapine • Clozaril
Desipramine • Norpramin
Desvenlafaxine • Pristiq
Dexmethylphenidate • Focalin
Dextroamphetamine/amphetamine • Adderall
Disulfiram • Antabuse
Doxepin • Prudoxin, Silenor
Droperidol • Inapsine
Duloxetine • Cymbalta
Escitalopram • Lexapro
Esketamine • Spravato
Eszopiclone • Lunesta
Fluoxetine • Prozac
Fluphenazine • Prolixin
Fluvoxamine • Luvox
Haloperidol • Haldol
Iloperidone • Fanapt
Imipramine • Tofranil
Isocarboxazid • Marplan
Lamotrigine • Lamictal
Levomilnacipran • Fetzima
Levothyroxine • Synthroid
Linezolid • Zyvox
Lisdexamfetamine • Vyvanse
Lithium • Eskalith, Lithobid
Loxapine • Loxitane
Lurasidone • Latuda
Maprotiline • Ludiomil
Methadone • Dolophine, Methadose
Methylphenidate • Ritalin, Concerta
Midazolam • Versed
Milnacipran • Savella
Mirtazapine • Remeron
Naltrexone • Revia, Vivitrol
Nefazodone • Serzone
Nortriptyline • Aventyl, Pamelor
Olanzapine • Zyprexa
Paliperidone • Invega
Paroxetine • Paxil
Perphenazine • Trilafon
Phenelzine • Nardil
Pimavanserin • Nuplazid
Prochlorperazine • Compro
Protriptyline • Vivactil
Quetiapine • Seroquel
Risperidone • Risperdal
Selegiline • Emsam
Sertraline • Zoloft
Thioridazine • Mellaril
Thiothixene • Navane
Tranylcypromine • Parnate
Trazodone • Desyrel, Oleptro
Trifluoperazine • Stelazine
Trimipramine • Surmontil
Valproate • Depakote
Varenicline • Chantix, Wellbutrin
Vilazodone • Viibryd
Venlafaxine • Effexor
Vortioxetine • Trintellix
Zaleplon • Sonata
Ziprasidone • Geodon
Zolpidem • Ambien