Comparison of chlorpromazine, haloperidol and pimozide in the treatment of phencyclidine psychosis: DA-2 receptor specificity.

Three neuroleptics were used to treat phencyclidine (PCP) psychosis. These included chlorpromazine, a DA-1 and DA-2 dopamine antagonist with noradrenergic effects; haloperidol, a predominantly DA-2 antagonist with noradrenergic effects; and pimozide a predominantly DA-2 antagonist with no noradrenergic activity. Three cohorts of randomly selected young white adult males were studied. Responses to haloperidol and pimozide were statistically equivalent and both were significantly superior to chlorpromazine. These results further support the role of the DA-2 receptor in PCP psychosis and tend to rule out a noradrenergic role. The authors therefore suggest that DA-2 blockers, such as haloperidol or pimozide be employed as treatment of choice in PCP psychosis.