Cimetidine-induced mental status changes: case report and literature review.

An apparent case of psychosis induced by cimetidine is reported. A 61-year-old Caucasian woman was hospitalized with chief complaints of left-sided paresthesias, headache, and vertigo. She had a history of hyperparathyroidism, thyroid insufficiency, and chronic but stable renal insufficiency. Admitting laboratory data indicated possible hepatic compromise. On day 16 of hospitalization, cimetidine (300 mg q 6 hr p.o.) was begun because of a falling hematocrit and guaiac-positive stools. Within 24 hours after cimetidine therapy was begun, the patient was confused, tearful, and disoriented. This confusional state continued during treatment with cimetidine, and was refractory to antipsychotic therapy. On day 5 of cimetidine therapy, the patient experienced visual and auditory hallucinations, and both cimetidine and antipsychotic drugs were discontinued. The patient was noted to be alert and oriented 24 hours later. A review of the literature revealed 30 cases of apparent cimetidine-induced CNS changes. Patients experiencing such reactions were typically elderly with compromised renal or hepatic failure, or both. Future studies on this topic should focus on predisposing patient factors and serum or cerebrospinal fluid concentrations of cimetidine associated with the symptomology.