Prolactin response to nemonapride, a new antipsychotic drug, in schizophrenic patients

The prolactin response to nemonapride, a new antipsychotic drug, was studied in 27 schizophrenic inpatients (12 males, 15 females). The daily dose of nemonapride was 18 mg/day, and the duration of treatment was 3 weeks. Plasma prolactin concentrations were measured by enzyme immunoassay. Nemonapride treatment significantly (p<0·01) increased prolactin concentrations at each week in both genders. The Δprolactin (the mean concentration during 3 weeks minus the pretreatment concentration) was significantly (p<0·01) greater in females (mean± SD, 81·6±57·8 ng/ml) than males (34·9±19·8 ng/ml). The present study thus shows that nemonapride treatment markedly increases prolactin concentrations in schizophrenic patients, with greater responses in females than males, suggesting a strong D2 receptor blockade property of the drug. © 1997 John Wiley & Sons, Ltd.