LHRH analogues in the treatment of endometriosis--comparative results with other treatments.

The induction of a state of hypo-oestrogenism has been found to be effective in the treatment of endometriosis. Continued administration of agonistic analogues of luteinizing hormone-releasing hormone (LHRH) results in the normal menstruating female developing normogonadotrophic-amenorrhoea with reduced circulating levels of oestradiol-17B, often within the menopausal range. Uncontrolled studies reported the efficacy of LHRH analogues in patients with mild, moderate and even severe endometriosis (American Fertility Society classification) following 6 months therapy. A number of large multi-centre randomized open or double blind trials comparing various LHRH analogues against danazol are currently underway. Published results available to date indicate that LHRH analogues and danazol are equally effective at reducing the symptoms of endometriosis and inducing complete or partial resolution of endometriotic deposits. Side-effects are, however, more severe with danazol therapy. The side-effects experienced with LHRH analogues are those expected from an induced state of hypo-oestrogenism--hot flushes, dry vagina, headaches, superficial dyspareunia--but are well tolerated by patients. The alterations observed in bone and calcium metabolism are comparable to those in the menopause--increased Ca++ loss and reversible loss of trabecular bone density have been reported. These effects may limit the duration and/or frequency of LHRH analogue treatment regimens. The valuable role of LHRH analogues in the treatment of endometriosis has been established and, as newer formulations become available, they are likely to play an increasingly important part in patient management.