Serum prolactin levels after a single and subchronic oral administration of chlorpromazine and sulpiride. A cross-over study in healthy volunteers.

The effect of a single antianxiety dose of chlorpromazine (100 mg) and sulpiride (200 mg) on serum prolactin and gonadotrophins was studied in 6 healthy women in a cross-over study. Another 10 healthy students, 5 women and 5 men, ingested cross-over sulpiride 50 mg t.i.d. for 2 weeks and chlorpromazine 10 mg t.i.d. for 1 week followed by 20 mg t.i.d. for the second week, and serum prolactin levels were measured on the 7th and 14th day after the beginning of the treatment. In acute study sulpiride caused a fivefold increase in serum prolactin at 1 h. Chlorpromazine induced a slower and smaller increase. Prolactin concentrations remained raised for at least 6 h. The initial raised prolactin concentration induced by sulpiride was associated with antidiuresis. The only change in gonadotrophins was the decrease of serum LH caused by chlorpromazine at 3 h. Subchronic administration of sulpiride (50 mg t.i.d.) caused in both sexes a significantly (P less than 0.05 to 0.01) greater increase of prolactin than did chlorpromazine (10 or 20 mg t.i.d.). It is concluded that in doses useful in the treatment of neurotic patients sulpiride causes a greater increase in serum prolactin levels than does chlorpromazine.