Introduction: Acute dystonic reactions are known extrapyramidal side effects of dopamine antagonists like metoclopramide. They typically respond to anticholinergic or antihistaminic agents such as diphenhydramine or benztropine. We present a rare case of severe metoclopramide-induced dystonia that was unresponsive to diphenhydramine but resolved with lorazepam, highlighting the importance of alternative therapeutic strategies in critical care settings.
Description: A 29-year-old previously healthy male with a history of marijuana use presented with nausea, vomiting, and diarrhea after suspected foodborne illness. Labs revealed leukocytosis, hypernatremia, acute kidney injury, and elevated CPK (24,000), attributed to cannabinoid hyperemesis syndrome vs gastroenteritis with rhabdomyolysis. He was started on IV fluids and empiric antibiotics. During hospitalization, he received IV metoclopramide for nausea and developed acute upper extremity spasms, back arching, diaphoresis, and drooling. The Rapid Response Team was called. He was alert, oriented, and hemodynamically stable. IV diphenhydramine (50 mg) and Benztropine was ineffective; however, 2 mg IV lorazepam resulted in rapid resolution of symptoms. The patient later recalled a similar reaction to metoclopramide years prior. It was added to his allergy list. No further episodes occurred. This case highlights the importance of recognizing acute dystonic reactions and considering lorazepam as an effective rescue therapy when antihistamines fail.
Discussion: Metoclopramide-induced dystonia is a recognized adverse event, especially in younger patients. While diphenhydramine is first-line therapy, this case illustrates that benzodiazepines like lorazepam may be effective when anticholinergic therapy fails. The precise mechanism may involve GABAergic inhibition of excessive dopaminergic blockade or modulation of muscle tone. Recognizing refractory dystonia early and promptly escalating therapy is essential in preventing further complications, including airway compromise or prolonged hospitalization.This case underscores the importance of identifying acute dystonic reactions in the inpatient setting and highlights lorazepam as a viable rescue therapy when diphenhydramine fails.
