Objective: The objective of this study was to investigate the hypothalamic-
pituitary-gonadal response to intrathecal opioids.
Patients: Thirty patients receiving intrathecal morphine for chronic nonmal
ignant pain were studied for clinical and biochemical evidence of hypogonad
ism. Ten men and 10 postmenopausal women with chronic pain of similar durat
ion but who were not receiving any form of opioid therapy acted as control
Results: Men and both premenopausal and postmenopausal women had evidence o
f hypogonadism with low levels of serum testosterone or estrogen coupled wi
th low levels of pituitary gonadotrophins. Control subjects had hormone lev
els in the expected range for their sex and age. Two men demonstrated recov
ery after ceasing intrathecal opioid therapy.
Conclusions: Hypogonadotrophic hypogonadism is a common complication of int
rathecal opioid therapy in both men and women.