To the Editor.—
Chlorzoxazone is an effective adjunctive drug used to treat acute muscle spasms owing to different etiologic factors.1 The most common side effects owing to chlorzoxazone are drowsiness and hepatic and gastrointestinal dysfunction. A report of a spasmodic torticollis-like syndrome that was evoked repeatedly after the ingestion of chlorzoxazone is presented, since this complication has been either not noted or well publicized.
Report of a Case.—
A 46-year-old woman came to a local emergency room to seek relief from muscle cramps in her neck. In the preceding eight months she had experienced seven previous episodes of a spasmodic, torticollis-like syndrome consisting of tonic deviation of the head to the right, tonic clenching of the teeth, and dysarthria. She usually took no prescription drugs, but did occasionally take overthe-counter, aspirin-containing products. In retrospect, all of these episodes occurred within two hours after the ingestion of chlorzoxazone, which had
Rosin MA. Chlorzoxazone-Induced Spasmodic Torticollis. JAMA. 1981;246(22):2575. doi:10.1001/jama.1981.03320220027010