Diphenhydramine abuse and detoxification: a brief review and case report

J Psychopharmacol. 2009 Jan;23(1):101-5. doi: 10.1177/0269881107083809. Epub 2008 Feb 28.


Many medicines available over the counter from pharmacies are known to have abuse potential, including diphenhydramine (DPH), an antihistamine with antimuscarinic properties used for the treatment of insomnia. We present a brief review of the literature describing DPH abuse, and report the case of GF, a 56 year old woman who was admitted to an inpatient addictions unit for detoxification from DPH. A literature search revealed five case reports of DPH abuse including a total of six patients, published between 1986 and 2001. All reported cases exhibited features of DSM-IV criteria for substance dependence, and there was an apparent link with antipsychotic usage. GF was treated with antipsychotics, and was using up to thirty 50 mg DPH tablets each day. She described feeling 'good and calm' and 'it stopped the tremors'. GF tolerated a gradual dose reduction schedule, and completed the detoxification programme relatively comfortably. She was discharged from the inpatient detoxification unit as planned, and had not relapsed at six months. The described case report highlights the importance of enquiring about non prescribed medication when taking a drug history. Similarly community pharmacists and GPs should be vigilant to excessive requests for DPH, particularly in patients with a psychotic illness.

Publication types

  • Case Reports

MeSH terms

  • Databases, Bibliographic
  • Diagnostic and Statistical Manual of Mental Disorders
  • Diphenhydramine / metabolism*
  • Diphenhydramine / toxicity*
  • Female
  • Histamine Antagonists / metabolism*
  • Histamine Antagonists / toxicity*
  • Humans
  • Inactivation, Metabolic / physiology*
  • Male
  • Middle Aged
  • Nonprescription Drugs / metabolism
  • Nonprescription Drugs / toxicity
  • Substance Abuse Treatment Centers
  • Time Factors


  • Histamine Antagonists
  • Nonprescription Drugs
  • Diphenhydramine