Selective dopamine D2 antagonist and prolactin response in acute schizophrenia--results from remoxipride studies. The Canadian Remoxipride Study Group.

1. In a double-blind dose finding study prolactin was assessed at baseline and end of treatment in three groups of acute schizophrenics receiving low, intermediate and high doses of remoxipride as compared to a controlled group that received haloperidol. 2. Remoxipride only in high doses (300-600 mg daily) has produced a modest increase in prolactin levels at endpoint as compared to the much higher increase in prolactin secretion that accompanied haloperidol treatment. 3. The weak effects on prolactin as well as the previously reported low incidence of extrapyramidal side effects confirm the profile of remoxipride as a selective dopamine D2 antagonist with preferential effects on the mesolimbic and mesocortical tracts. 4. Male responders to either remoxipride or haloperidol treatment had significantly higher baseline prolactin levels regardless of dose and drug used. In females, there was no difference in baseline prolactin between responders and nonresponders.