Edward G. Hall, MD

CASE Numb and confused
Mr. L, age 17, is admitted to the hospital after ingesting 24 diphenhydramine 25-mg tablets in 3 hours as a possible suicide attempt. His parents witnessed him behaving strangely and brought him to the hospital. They state that their son was visibly agitated and acting inap­propriately. He was seen talking to birds, trees, and the walls of the house.

Mr. L says he is upset because he broke up with his girlfriend a week earlier after she asked if they could “take a break.” He says that he took the diphenhydramine because he wanted to “get numb” to deal with the emotional stress caused by the break-up.

After the break-up, Mr. L experienced middle-to-late insomnia and was unable to get more than 3 or 4 hours of sleep a night. He reports significant fatigue, depressed mood, anhedonia, impaired concentration, and psy­chomotor retardation. He denies homicidal ide­ation or auditory and visual hallucinations.

As an aside, Mr. L reports that, for the past year, he had difficulties with gender identity, sometimes thinking that he might be better off if he had been born a girl and that he felt uncomfortable in a male body.

Which treatment option would you choose for Mr. L’s substance abuse?
   a) refer him to a 12-step program
   b) begin supportive measures
   c) administer activated charcoal
   d) prescribe a benzodiazepine to control agitation

The authors’ observations
As youths gain increasing access to medical and pharmaceutical knowledge through the Internet and other sources, it appears that adolescent drug abuse has, in part, shifted toward more easily attain­able over-the-counter (OTC) medications. Diphenhydramine, a first-generation anti­histamine, can be abused for its effects on the CNS, such as disturbed coordination, irritability, paresthesia, blurred vision, and depression. Effects of diphenhydramine are increased by the presence of alcohol, monoamine oxidase inhibitors, diazepam, hypnotics, sedatives, tranquilizers, and other CNS depressants. In 2011, diphen­hydramine abuse was involved in 19,012 emergency room visits, of which 9,301 were for drug-related suicide attempts.¹

Diphenhydramine is an inverse agonist of the histamine H1 receptor.² It is a mem­ber of the ethanolamine subclass of antihis­taminergic agents.³ By reversing the effects of histamine on capillaries, diphenhydramine can reduce the intensity of allergic symptoms. Diphenhydramine also crosses the blood–brain barrier and antagonizes H1 receptors centrally.

Used as a common sleep aid and allergy medication, the drug works primarily as an H1 receptor partial agonist, but also is a strong competitive antagonist at musca­rinic acetylcholine receptors.4 It is abused for its sedative effects and its capacity to cause delirium and hallucinations.5 Diphenhydramine can have a stimula­tory effect in children and young adults, instead of the sedating properties seen in adults.6 Such misuse is concerning because diphenhydramine overdose can lead to delirium, confusion, and halluci­nations, tachycardia, seizures, mydria­sis, xerostomia, urinary retention, ileus, anhidrosis, and hyperthermia. In severe cases it has been associated with cardiac arrhythmias, rhabdomyolysis, status epi­lepticus, and death.4,6 Neurologic symp­toms of diphenhydramine overdose are listed in Table 1.

HISTORY Polysubstance abuse
Mr. L has a 2-year history of major depressive disorder and a history of Cannabis abuse with physiological dependence; Robitussin (base active ingredient, guaifenesin) and hydroco­done abuse with physiological dependence; 3,4-methylenedioxymethamphetamine (MDMA) abuse; and diphenhydramine abuse. He also has a history of gender dysphoria, although he reports that these feelings have become less severe over the past year.

Mr. L attends bi-weekly appointments with an outpatient psychiatrist and report­edly adheres to his medication regimen: fluoxetine, 40 mg/d, and risperidone, 1 mg at bedtime. He denies previous suicidal ide­ation, suicide attempts, homicidal ideation, or homicidal attempts. He reports no history of physical, sexual, or emotional abuse. He gets good grades in school and has no outstanding academic problems.

Mr. L began using Cannabis at age 14; his last use was 3 weeks before admission. He is guarded about his use of Robitussin, hydroco­done, and MDMA. However, Mr. L reports that he has researched diphenhydramine on the internet and believes that he can safely take up to 1,200 mg without overdosing. He reports normally taking 450 mg of diphenhydramine daily. Mr. L reports difficulty urinating after using diphenhydramine but no other physical complaints.

Mr. L lives with his father and stepmother and has a history of one psychiatric hospital­ization at a different facility 2 months ago, fol­lowed by outpatient therapy. He obtained his Graduate Equivalency Diploma (GED) and plans to attend college.

At age 5, Mr. L emigrated from Turkey to the United States with his parents. His mother returned to Turkey when he was age 6 and has had no contact with her son since. Whenever Mr. L visits Turkey with his father, the patient refuses to see her, as per collaterals. He gets along well with his stepmother, who is his maternal aunt. Mr. L has been bullied at school and reportedly has few friends.

 

On mental status examination, Mr. L has an appropriate appearance and appears to be his stated age. He shows good eye con­tact and is cooperative. Muscle tone and gait are within normal limits. He has no abnormal movements. Speech, thought processes, and associations are normal. He denies auditory hallucinations, visual hallucinations, suicidal ideation (although he presented with a prob­able suicide attempt), or homicidal ideation. No delusions are elicited.

Mr. L shows poor judgment about his drug use and situation. He demonstrates limited insight, because he says his only goal is to get out of the hospital. He is alert, awake, and oriented to person, place, and time. He shows no memory or knowledge impairment. He appears euthymic with an inappropriate and constricted affect. On neurologic exam, he had mild tremors in his hands. The authors’ observationsTreatment for diphenhydramine over­dose should begin quickly to prevent life-threatening effects and reduce the risk for mortality. The toxin can be removed from the patient’s GI tract with activated char­coal or gastric lavage if the patient presents within 1 hour of ingesting the substance. Administering IV fluids will prevent dehy­dration. Cardiac functioning is monitored and benzodiazepines could be adminis­tered to manage seizures.

Key elements of a toxicologic physical examination include:
   • eyes: pupillary size, symmetry, and response to light (vertical or horizontal nystagmus)
   • oropharynx: moist or dry mucous membranes, presence or absence of the gag reflex, distinctive odors
   • abdomen: presence or absence and quality of bowel sounds
   • skin: warm and dry, warm and sweaty, or cool
   • neurologic: level of consciousness and mental status, presence of tremors, seizures, or other movement disorders, presence or absence and quality of deep tendon reflexes.⁷

If a child or adolescent patient cannot communicate how much of a drug he (she) has ingested, questions to ask parents or other informants include:
   • Was the medication purchased recently, and if so was the bottle or box full before the patient took the pills?
   • If the medication was not new, how many pills were in the bottle before the patient got to it?
   • If the medication was prescribed, how many pills were originally prescribed, when was the medication prescribed, and how many pills were already taken prior to the patient getting to the bottle?
   • How many pills were left in the bottle?
   • How many pills were seen around the area where the patient was found?
   • How many pills were found in the patient’s mouth?⁷

Recommendations
It is well known that OTC medication abuse is a growing medical problem (Table 2). Antihistamines, including diphenhydramine, are readily available to minors and adults. Because of the powerful sedating effects of antihistamines, many adolescent health practitioners give them to patients who have insomnia as a sleep aid.⁸ As in our case, antihistamines are used recreationally for their hallucinogenic effects, at dosages of 300 to 700 mg.⁹ Severe symptoms of toxicity, such as delirium and psychosis, seizures, and coma, occur at dosages ≥1,000 mg.⁹

With growing abuse of these medications, we aim to encourage detailed history taking about abuse of OTC drugs, especially diphenhydramine in adolescent patients.


Outcome Improvement, discharge
Mr. L is given a dual diagnosis of diphenhydramine-induced psychotic disorder with
hallucinations and diphenhydramine-induced depressive disorder, both with onset during intoxication. He also is given a provisional diagnosis of psychotic disorder not otherwise specified and major depressive disorder. Last, he is given a diagnosis of Cannabis dependence with physiological dependence, MDMA abuse, hydrocodone abuse, and Robitussin abuse.

Mr. L is maintained on fluoxetine, 40 mg/d, and risperidone, 1 mg at bedtime and 0.5 mg in the morning. He receives milieu, individual, group, recreational, and medical therapy while in the hospital. Symptoms abate and he is discharged with a plan to follow up with outpatient providers.

Bottom Line
Abuse of over-the-counter (OTC) drugs, such as diphenhydramine, among youths is a growing problem. Remember to question adolescents who appear intoxicated or to have overdosed not only about abuse of alcohol and illicit substances but also of common—and easily and legally accessible—OTC drugs.

Related Resources
• Carr BC. Efficacy, abuse, and toxicity of over-the-counter cough and cold medicines in the pediatric population. Curr Opin Pediatr. 2006;18(2):184-188.
• Thomas A, Nallur DG, Jones N, et al. Diphenhydramine abuse and detoxification: a brief review and case report. J Psychopharmacol. 2009;23(1):101-105.

Drug Brand Names
Diazepam • Valium                      Hydrocodone • Vicodin
Diphenhydramine • Benadryl        Risperidone • Risperdal
Fluoxetine • Prozac

Disclosures
The authors report no financial relationships with any company whose products are mentioned in this article or with manufacturers of competing products.

CASE Numb and confused
Mr. L, age 17, is admitted to the hospital after ingesting 24 diphenhydramine 25-mg tablets in 3 hours as a possible suicide attempt. His parents witnessed him behaving strangely and brought him to the hospital. They state that their son was visibly agitated and acting inap­propriately. He was seen talking to birds, trees, and the walls of the house.

Mr. L says he is upset because he broke up with his girlfriend a week earlier after she asked if they could “take a break.” He says that he took the diphenhydramine because he wanted to “get numb” to deal with the emotional stress caused by the break-up.

After the break-up, Mr. L experienced middle-to-late insomnia and was unable to get more than 3 or 4 hours of sleep a night. He reports significant fatigue, depressed mood, anhedonia, impaired concentration, and psy­chomotor retardation. He denies homicidal ide­ation or auditory and visual hallucinations.

As an aside, Mr. L reports that, for the past year, he had difficulties with gender identity, sometimes thinking that he might be better off if he had been born a girl and that he felt uncomfortable in a male body.

Which treatment option would you choose for Mr. L’s substance abuse?
   a) refer him to a 12-step program
   b) begin supportive measures
   c) administer activated charcoal
   d) prescribe a benzodiazepine to control agitation

The authors’ observations
As youths gain increasing access to medical and pharmaceutical knowledge through the Internet and other sources, it appears that adolescent drug abuse has, in part, shifted toward more easily attain­able over-the-counter (OTC) medications. Diphenhydramine, a first-generation anti­histamine, can be abused for its effects on the CNS, such as disturbed coordination, irritability, paresthesia, blurred vision, and depression. Effects of diphenhydramine are increased by the presence of alcohol, monoamine oxidase inhibitors, diazepam, hypnotics, sedatives, tranquilizers, and other CNS depressants. In 2011, diphen­hydramine abuse was involved in 19,012 emergency room visits, of which 9,301 were for drug-related suicide attempts.¹

Diphenhydramine is an inverse agonist of the histamine H1 receptor.² It is a mem­ber of the ethanolamine subclass of antihis­taminergic agents.³ By reversing the effects of histamine on capillaries, diphenhydramine can reduce the intensity of allergic symptoms. Diphenhydramine also crosses the blood–brain barrier and antagonizes H1 receptors centrally.

Used as a common sleep aid and allergy medication, the drug works primarily as an H1 receptor partial agonist, but also is a strong competitive antagonist at musca­rinic acetylcholine receptors.4 It is abused for its sedative effects and its capacity to cause delirium and hallucinations.5 Diphenhydramine can have a stimula­tory effect in children and young adults, instead of the sedating properties seen in adults.6 Such misuse is concerning because diphenhydramine overdose can lead to delirium, confusion, and halluci­nations, tachycardia, seizures, mydria­sis, xerostomia, urinary retention, ileus, anhidrosis, and hyperthermia. In severe cases it has been associated with cardiac arrhythmias, rhabdomyolysis, status epi­lepticus, and death.4,6 Neurologic symp­toms of diphenhydramine overdose are listed in Table 1.

HISTORY Polysubstance abuse
Mr. L has a 2-year history of major depressive disorder and a history of Cannabis abuse with physiological dependence; Robitussin (base active ingredient, guaifenesin) and hydroco­done abuse with physiological dependence; 3,4-methylenedioxymethamphetamine (MDMA) abuse; and diphenhydramine abuse. He also has a history of gender dysphoria, although he reports that these feelings have become less severe over the past year.

Mr. L attends bi-weekly appointments with an outpatient psychiatrist and report­edly adheres to his medication regimen: fluoxetine, 40 mg/d, and risperidone, 1 mg at bedtime. He denies previous suicidal ide­ation, suicide attempts, homicidal ideation, or homicidal attempts. He reports no history of physical, sexual, or emotional abuse. He gets good grades in school and has no outstanding academic problems.

Mr. L began using Cannabis at age 14; his last use was 3 weeks before admission. He is guarded about his use of Robitussin, hydroco­done, and MDMA. However, Mr. L reports that he has researched diphenhydramine on the internet and believes that he can safely take up to 1,200 mg without overdosing. He reports normally taking 450 mg of diphenhydramine daily. Mr. L reports difficulty urinating after using diphenhydramine but no other physical complaints.

Mr. L lives with his father and stepmother and has a history of one psychiatric hospital­ization at a different facility 2 months ago, fol­lowed by outpatient therapy. He obtained his Graduate Equivalency Diploma (GED) and plans to attend college.

At age 5, Mr. L emigrated from Turkey to the United States with his parents. His mother returned to Turkey when he was age 6 and has had no contact with her son since. Whenever Mr. L visits Turkey with his father, the patient refuses to see her, as per collaterals. He gets along well with his stepmother, who is his maternal aunt. Mr. L has been bullied at school and reportedly has few friends.

 

On mental status examination, Mr. L has an appropriate appearance and appears to be his stated age. He shows good eye con­tact and is cooperative. Muscle tone and gait are within normal limits. He has no abnormal movements. Speech, thought processes, and associations are normal. He denies auditory hallucinations, visual hallucinations, suicidal ideation (although he presented with a prob­able suicide attempt), or homicidal ideation. No delusions are elicited.

Mr. L shows poor judgment about his drug use and situation. He demonstrates limited insight, because he says his only goal is to get out of the hospital. He is alert, awake, and oriented to person, place, and time. He shows no memory or knowledge impairment. He appears euthymic with an inappropriate and constricted affect. On neurologic exam, he had mild tremors in his hands. The authors’ observationsTreatment for diphenhydramine over­dose should begin quickly to prevent life-threatening effects and reduce the risk for mortality. The toxin can be removed from the patient’s GI tract with activated char­coal or gastric lavage if the patient presents within 1 hour of ingesting the substance. Administering IV fluids will prevent dehy­dration. Cardiac functioning is monitored and benzodiazepines could be adminis­tered to manage seizures.

Key elements of a toxicologic physical examination include:
   • eyes: pupillary size, symmetry, and response to light (vertical or horizontal nystagmus)
   • oropharynx: moist or dry mucous membranes, presence or absence of the gag reflex, distinctive odors
   • abdomen: presence or absence and quality of bowel sounds
   • skin: warm and dry, warm and sweaty, or cool
   • neurologic: level of consciousness and mental status, presence of tremors, seizures, or other movement disorders, presence or absence and quality of deep tendon reflexes.⁷

If a child or adolescent patient cannot communicate how much of a drug he (she) has ingested, questions to ask parents or other informants include:
   • Was the medication purchased recently, and if so was the bottle or box full before the patient took the pills?
   • If the medication was not new, how many pills were in the bottle before the patient got to it?
   • If the medication was prescribed, how many pills were originally prescribed, when was the medication prescribed, and how many pills were already taken prior to the patient getting to the bottle?
   • How many pills were left in the bottle?
   • How many pills were seen around the area where the patient was found?
   • How many pills were found in the patient’s mouth?⁷

Recommendations
It is well known that OTC medication abuse is a growing medical problem (Table 2). Antihistamines, including diphenhydramine, are readily available to minors and adults. Because of the powerful sedating effects of antihistamines, many adolescent health practitioners give them to patients who have insomnia as a sleep aid.⁸ As in our case, antihistamines are used recreationally for their hallucinogenic effects, at dosages of 300 to 700 mg.⁹ Severe symptoms of toxicity, such as delirium and psychosis, seizures, and coma, occur at dosages ≥1,000 mg.⁹

With growing abuse of these medications, we aim to encourage detailed history taking about abuse of OTC drugs, especially diphenhydramine in adolescent patients.


Outcome Improvement, discharge
Mr. L is given a dual diagnosis of diphenhydramine-induced psychotic disorder with
hallucinations and diphenhydramine-induced depressive disorder, both with onset during intoxication. He also is given a provisional diagnosis of psychotic disorder not otherwise specified and major depressive disorder. Last, he is given a diagnosis of Cannabis dependence with physiological dependence, MDMA abuse, hydrocodone abuse, and Robitussin abuse.

Mr. L is maintained on fluoxetine, 40 mg/d, and risperidone, 1 mg at bedtime and 0.5 mg in the morning. He receives milieu, individual, group, recreational, and medical therapy while in the hospital. Symptoms abate and he is discharged with a plan to follow up with outpatient providers.

Bottom Line
Abuse of over-the-counter (OTC) drugs, such as diphenhydramine, among youths is a growing problem. Remember to question adolescents who appear intoxicated or to have overdosed not only about abuse of alcohol and illicit substances but also of common—and easily and legally accessible—OTC drugs.

Related Resources
• Carr BC. Efficacy, abuse, and toxicity of over-the-counter cough and cold medicines in the pediatric population. Curr Opin Pediatr. 2006;18(2):184-188.
• Thomas A, Nallur DG, Jones N, et al. Diphenhydramine abuse and detoxification: a brief review and case report. J Psychopharmacol. 2009;23(1):101-105.

Drug Brand Names
Diazepam • Valium                      Hydrocodone • Vicodin
Diphenhydramine • Benadryl        Risperidone • Risperdal
Fluoxetine • Prozac

Disclosures
The authors report no financial relationships with any company whose products are mentioned in this article or with manufacturers of competing products.

CASE Numb and confused
Mr. L, age 17, is admitted to the hospital after ingesting 24 diphenhydramine 25-mg tablets in 3 hours as a possible suicide attempt. His parents witnessed him behaving strangely and brought him to the hospital. They state that their son was visibly agitated and acting inap­propriately. He was seen talking to birds, trees, and the walls of the house.

Mr. L says he is upset because he broke up with his girlfriend a week earlier after she asked if they could “take a break.” He says that he took the diphenhydramine because he wanted to “get numb” to deal with the emotional stress caused by the break-up.

After the break-up, Mr. L experienced middle-to-late insomnia and was unable to get more than 3 or 4 hours of sleep a night. He reports significant fatigue, depressed mood, anhedonia, impaired concentration, and psy­chomotor retardation. He denies homicidal ide­ation or auditory and visual hallucinations.

As an aside, Mr. L reports that, for the past year, he had difficulties with gender identity, sometimes thinking that he might be better off if he had been born a girl and that he felt uncomfortable in a male body.

Which treatment option would you choose for Mr. L’s substance abuse?
   a) refer him to a 12-step program
   b) begin supportive measures
   c) administer activated charcoal
   d) prescribe a benzodiazepine to control agitation

The authors’ observations
As youths gain increasing access to medical and pharmaceutical knowledge through the Internet and other sources, it appears that adolescent drug abuse has, in part, shifted toward more easily attain­able over-the-counter (OTC) medications. Diphenhydramine, a first-generation anti­histamine, can be abused for its effects on the CNS, such as disturbed coordination, irritability, paresthesia, blurred vision, and depression. Effects of diphenhydramine are increased by the presence of alcohol, monoamine oxidase inhibitors, diazepam, hypnotics, sedatives, tranquilizers, and other CNS depressants. In 2011, diphen­hydramine abuse was involved in 19,012 emergency room visits, of which 9,301 were for drug-related suicide attempts.¹

Diphenhydramine is an inverse agonist of the histamine H1 receptor.² It is a mem­ber of the ethanolamine subclass of antihis­taminergic agents.³ By reversing the effects of histamine on capillaries, diphenhydramine can reduce the intensity of allergic symptoms. Diphenhydramine also crosses the blood–brain barrier and antagonizes H1 receptors centrally.

Used as a common sleep aid and allergy medication, the drug works primarily as an H1 receptor partial agonist, but also is a strong competitive antagonist at musca­rinic acetylcholine receptors.4 It is abused for its sedative effects and its capacity to cause delirium and hallucinations.5 Diphenhydramine can have a stimula­tory effect in children and young adults, instead of the sedating properties seen in adults.6 Such misuse is concerning because diphenhydramine overdose can lead to delirium, confusion, and halluci­nations, tachycardia, seizures, mydria­sis, xerostomia, urinary retention, ileus, anhidrosis, and hyperthermia. In severe cases it has been associated with cardiac arrhythmias, rhabdomyolysis, status epi­lepticus, and death.4,6 Neurologic symp­toms of diphenhydramine overdose are listed in Table 1.

HISTORY Polysubstance abuse
Mr. L has a 2-year history of major depressive disorder and a history of Cannabis abuse with physiological dependence; Robitussin (base active ingredient, guaifenesin) and hydroco­done abuse with physiological dependence; 3,4-methylenedioxymethamphetamine (MDMA) abuse; and diphenhydramine abuse. He also has a history of gender dysphoria, although he reports that these feelings have become less severe over the past year.

Mr. L attends bi-weekly appointments with an outpatient psychiatrist and report­edly adheres to his medication regimen: fluoxetine, 40 mg/d, and risperidone, 1 mg at bedtime. He denies previous suicidal ide­ation, suicide attempts, homicidal ideation, or homicidal attempts. He reports no history of physical, sexual, or emotional abuse. He gets good grades in school and has no outstanding academic problems.

Mr. L began using Cannabis at age 14; his last use was 3 weeks before admission. He is guarded about his use of Robitussin, hydroco­done, and MDMA. However, Mr. L reports that he has researched diphenhydramine on the internet and believes that he can safely take up to 1,200 mg without overdosing. He reports normally taking 450 mg of diphenhydramine daily. Mr. L reports difficulty urinating after using diphenhydramine but no other physical complaints.

Mr. L lives with his father and stepmother and has a history of one psychiatric hospital­ization at a different facility 2 months ago, fol­lowed by outpatient therapy. He obtained his Graduate Equivalency Diploma (GED) and plans to attend college.

At age 5, Mr. L emigrated from Turkey to the United States with his parents. His mother returned to Turkey when he was age 6 and has had no contact with her son since. Whenever Mr. L visits Turkey with his father, the patient refuses to see her, as per collaterals. He gets along well with his stepmother, who is his maternal aunt. Mr. L has been bullied at school and reportedly has few friends.

 

On mental status examination, Mr. L has an appropriate appearance and appears to be his stated age. He shows good eye con­tact and is cooperative. Muscle tone and gait are within normal limits. He has no abnormal movements. Speech, thought processes, and associations are normal. He denies auditory hallucinations, visual hallucinations, suicidal ideation (although he presented with a prob­able suicide attempt), or homicidal ideation. No delusions are elicited.

Mr. L shows poor judgment about his drug use and situation. He demonstrates limited insight, because he says his only goal is to get out of the hospital. He is alert, awake, and oriented to person, place, and time. He shows no memory or knowledge impairment. He appears euthymic with an inappropriate and constricted affect. On neurologic exam, he had mild tremors in his hands. The authors’ observationsTreatment for diphenhydramine over­dose should begin quickly to prevent life-threatening effects and reduce the risk for mortality. The toxin can be removed from the patient’s GI tract with activated char­coal or gastric lavage if the patient presents within 1 hour of ingesting the substance. Administering IV fluids will prevent dehy­dration. Cardiac functioning is monitored and benzodiazepines could be adminis­tered to manage seizures.

Key elements of a toxicologic physical examination include:
   • eyes: pupillary size, symmetry, and response to light (vertical or horizontal nystagmus)
   • oropharynx: moist or dry mucous membranes, presence or absence of the gag reflex, distinctive odors
   • abdomen: presence or absence and quality of bowel sounds
   • skin: warm and dry, warm and sweaty, or cool
   • neurologic: level of consciousness and mental status, presence of tremors, seizures, or other movement disorders, presence or absence and quality of deep tendon reflexes.⁷

If a child or adolescent patient cannot communicate how much of a drug he (she) has ingested, questions to ask parents or other informants include:
   • Was the medication purchased recently, and if so was the bottle or box full before the patient took the pills?
   • If the medication was not new, how many pills were in the bottle before the patient got to it?
   • If the medication was prescribed, how many pills were originally prescribed, when was the medication prescribed, and how many pills were already taken prior to the patient getting to the bottle?
   • How many pills were left in the bottle?
   • How many pills were seen around the area where the patient was found?
   • How many pills were found in the patient’s mouth?⁷

Recommendations
It is well known that OTC medication abuse is a growing medical problem (Table 2). Antihistamines, including diphenhydramine, are readily available to minors and adults. Because of the powerful sedating effects of antihistamines, many adolescent health practitioners give them to patients who have insomnia as a sleep aid.⁸ As in our case, antihistamines are used recreationally for their hallucinogenic effects, at dosages of 300 to 700 mg.⁹ Severe symptoms of toxicity, such as delirium and psychosis, seizures, and coma, occur at dosages ≥1,000 mg.⁹

With growing abuse of these medications, we aim to encourage detailed history taking about abuse of OTC drugs, especially diphenhydramine in adolescent patients.


Outcome Improvement, discharge
Mr. L is given a dual diagnosis of diphenhydramine-induced psychotic disorder with
hallucinations and diphenhydramine-induced depressive disorder, both with onset during intoxication. He also is given a provisional diagnosis of psychotic disorder not otherwise specified and major depressive disorder. Last, he is given a diagnosis of Cannabis dependence with physiological dependence, MDMA abuse, hydrocodone abuse, and Robitussin abuse.

Mr. L is maintained on fluoxetine, 40 mg/d, and risperidone, 1 mg at bedtime and 0.5 mg in the morning. He receives milieu, individual, group, recreational, and medical therapy while in the hospital. Symptoms abate and he is discharged with a plan to follow up with outpatient providers.

Bottom Line
Abuse of over-the-counter (OTC) drugs, such as diphenhydramine, among youths is a growing problem. Remember to question adolescents who appear intoxicated or to have overdosed not only about abuse of alcohol and illicit substances but also of common—and easily and legally accessible—OTC drugs.

Related Resources
• Carr BC. Efficacy, abuse, and toxicity of over-the-counter cough and cold medicines in the pediatric population. Curr Opin Pediatr. 2006;18(2):184-188.
• Thomas A, Nallur DG, Jones N, et al. Diphenhydramine abuse and detoxification: a brief review and case report. J Psychopharmacol. 2009;23(1):101-105.

Drug Brand Names
Diazepam • Valium                      Hydrocodone • Vicodin
Diphenhydramine • Benadryl        Risperidone • Risperdal
Fluoxetine • Prozac

Disclosures
The authors report no financial relationships with any company whose products are mentioned in this article or with manufacturers of competing products.