Central anticholinergic syndrome after ofloxacin overdose and therapeutic doses of diphenhydramine and chlormezanone.

A 14-year-old female with no history of psychiatric disease ingested an unknown amount of ofloxacin, diphenhydramine and chlormezanone after an argument with her patients. Approximately 12 hours after ingestion, the patient was admitted to the hospital in a delirious state with extreme mydriasis and warm and dry skin. Analytical data on admission were consistent with ofloxacin overdose and ingestion of therapeutic doses of diphenhydramine and chlormezanone. The patient received activated charcoal and forced diuresis was instituted. Psychosis and anticholinergic symptoms lasted in the next 2 days. On day 3, the psychotic and anticholinergic symptoms were nearly completely reversed by 2 mg physostigmine salicylate, given IV x 2. Since anticholinergic symptoms have not been observed after ofloxacin overdose or after therapeutic doses of diphenhydramine or chlormezanone, this case suggests a potentiation of the anticholinergic effects of diphenhydramine and chlormezanone by ofloxacin overdose.