Antihistamine Drug Misuse and Dependency in Headache Patients: A Case Series in a Tertiary Care Headache Center

Abstract

Aims: To report antihistamine abuse at a tertiary headache center including 6 patients who meet the criteria for substance abuse for intramuscular diphenhydramine (DPH). Presentation of the Cases: Six patients were identified who were prescribed intramuscular DPH and developed escalating drug use. All patients were female, with a mean age of 40.6 (32-53), with diagnosis of medication overuse headache. Five had chronic migraine and 1 new daily persistent headache. All 6 patients were disabled. Three patients had history of misuse of other drugs including benztropine, hydromorphone and clonazepam. Comorbid psychiatric disorders included 3 patients with major depressive disorder, 2 with ADHD, 1 with post-traumatic stress disorder and social phobia. All of these patients had a history of receiving intravenous DPH as part of their migraine treatment to avoid complications from neuroleptics. Discussion and Conclusion: A literature search revealed eight case reports of DPH abuse