The effect of fluphenazine on basal prolactin concentrations

The effect of fluphenazine on basal human prolactin (hPRL) concentrations was studied in 10 male schizophrenics who had received fluphenazine treatment for at least 6 months, in 10 male alcoholics before and during the first week of fluphenazine treatment and in 8 alcoholics at daily intervals before and after treatment. The results were compared with basal hPRL concentrations in 17 healthy male controls. Investigations involved giving fluphenazine (Modecate)by intramuscular injection and taking blood samples at appropriate intervals by venepuncture. Basal hPRL concentrations were significantly increased in the schizophrenics. The alcoholics showed a significant rise in hPRL concentrations after fluphenazine but there was considerable variation in hPRL levels between individual patients. Most patients showed marked elevation of daily hPRL levels with peak concentrations occurring 5--6 days after the injection. The results demonstrate that fluphenazine elevates basal hPRL levels and the variation between levels of individual patients merits further investigation.