Daytime variation in serum prolactin level in patients receiving oral and depot antipsychotic medication
Goode, D.J.; Meltzer, H.Y.; Fang, V.S.
Biological Psychiatry 16(7): 653-662
1981
ISSN/ISBN: 0006-3223 PMID: 7196775 Document Number: 175500
Serum prolactin levels in psychiatric inpatients were measured at 0800 h prior to administration or oral chlorpromazine (CPZ) at 0900 and at hourly intervals throughout the day until 1500 h. Sixteen patients receiving CPZ 400 mg in equally divided doses of 200 mg twice daily at 0900 and 2100 h and 6 patients who had received fluphenazine decanoate (FD) in doses of 25-75 mg 2-3 wk prior to study were evaluated. In patients receiving oral CPZ, serum prolactin levels were elevated in the 0800 h samples; serum prolactin levels decreased between 0800-1000 h and then increased sharply, reaching their peak from 1100-1400 h. Serum prolactin levels were moderately elevated but relatively stable throughout the day in patients who had received i.m. FD. The 0800 h serum prolactin levels were correlated with the peak serum prolactin levels during the day in female patients receiving oral CPZ but not in male patients. The lack of correlation between base line and peak serum prolactin levels in male patients is most likely due to interference from the sleep-induced prolactin increase in 0800 h samples. Serum prolactin levels at 0900 h were significantly correlated with peak serum prolactin levels in both male and female patients. The importance of determining diurnal variation in serum prolactin levels in psychiatric patients is discussed.