Acute onset of orofacial dystonia from promethazine treatment: A case report.

Rationale: Promethazine is an antihistamine agent used commonly for nausea and allergy. Along with its anticholinergic and antidopaminergic functions, promethazine is also used for psychiatric symptoms, such as troubling sleep, anxiety, and agitation. Previous studies have reported that promethazine may occasionally elicit acute dystonia in some individuals, especially for young children and pregnant women. Patient concerns: The 68-year-old female patient was admitted to our hospital because of feeling anxious and intermittent palpitation for over 1 year. She developed acute orofacial dystonia following promethazine treatment. Diagnoses: Her diagnoses was generalized anxiety disorder. Interventions: Discontinuation of the offending agent, promethazine, and injection of Botulinum toxin. Outcomes: The acute orofacial dystonia was finally alleviated by local injection of Botulinum toxin. Lessons: Careful assessment of the risk of developing acute dystonia is also needed in old patients when initiating the promethazine treatment.