Diphenhydramine induced acute dystonia: a case report

Area of Science:

• Emergency Medicine
• Clinical Pharmacology
• Neuroscience

Background:

• Acute dystonia is a significant challenge in emergency settings.
• Drug-induced dystonia is infrequently documented in medical literature.
• Diphenhydramine is rarely implicated as a cause of dystonic reactions.

Observation:

• A 25-year-old female experienced an acute dystonic reaction after receiving intravenous diphenhydramine for an allergic reaction.
• The patient was administered 25 mg of intravenous diphenhydramine.
• The reaction manifested shortly after drug administration.

Findings:

• Diphenhydramine can precipitate acute dystonic reactions, even at standard doses.
• This adverse reaction, though rare, is severe and requires prompt management.
• The patient was successfully treated with diazepam and monitored.

Implications:

• Diphenhydramine-induced acute dystonia underscores the importance of recognizing idiosyncratic drug reactions.
• Further investigation into drug metabolism and patient phenotypes is warranted to understand susceptibility to such adverse events.
• Clinicians should be vigilant for dystonic reactions when prescribing diphenhydramine, especially in emergency situations.