Chlorpromazine vs. meperidine in the treatment of phencyclidine psychosis.

Patients with phencyclidine psychosis were treated with two 50 mg injections of either chlorpromazine (N = 10) or meperidine (N = 10). The chlorpromazine-treated group responded more rapidly, but the meperidine-treated group had greater overall improvement. It is suggested that meperidine may have a role in the emergency treatment of phencyclidine psychosis. These findings may provide support for the hypothesis that dopaminergic psychosis is mediated by opioids.