[Dysfunction of the hypothalamo-hypophyseal-gonadal axis induced by histamine H2 antagonists. Review of the literature and personal observations].

The effects of the H2 blockers most commonly used for treating ulcers (CMT + RNT) on the hypothalamic-hypophyseal-gonadal axis are analysed. The following conclusions may be drawn form the literature and from personal studies: a) Basal levels of PRL increase significantly after an i.v. bolus of CMT and, very probably, in the first few days of oral treatment. b) RNT orally or i.v., in standard therapeutic doses, has no effect on the secretion of prolactin which is only influenced by higher i.v. doses. c) From points a) and b) it would seem that H2 blockers determine PRL increases by interference at a central level in the histaminergic neurotransmission system. d) The mechanisms for determining alterations in LH secretion, secretory spikes and their frequency have not yet been clarified and are not even unanimously recognised. e) The gynaecomastia, galactorrhoea, amenorrhoea and impotence--reported only after long-term cimetidine treatment--can probably be attributed to the specific antiandrogen receptor property of CMT. f) The onset of menstrual problems or of modifications in sexual behaviour in fertile patients, should however be checked and their basal PRL monitored if necessary.