Danazol in the treatment of endometriosis and infertility

Endometriosis is an enigmatic condition of unknown cause and poorly understood histogenesis. It affects women in their reproductive years limiting their fertility and seriously impairing their health. It is not entirely clear what is the mechanism of infertility associated with endometriosis but it is well accepted that treatment of the latter improves significantly chances for conception. Danazol is a synthetic steroid, derivative of 17 alpha-ethinyl testosterone. It suppresses ovarian function through a direct inhibitory effect on ovarian steroidogenesis and through inhibition of FSH and LH secretion. The drug is a mild androgen but has no estrogenic or progestational properties. In normally cycling women danazol induces the state of pseudomenopause characterized by complete suppression of ovarian function, amenorrhea and hypoestrogenic state. Uterine endometrium and ectopic endometrium undergo atrophy during treatment, resulting in a regression and disappearance of endometriosis. The therapy should commence with the onset of the menstrual period and should be continued for three to six months or longer depending on the initial extent of the disease and a clinical response. The clinical and symptomatic improvement and disappearance of endometriosis is observed in over 80% of the patients. The corrected pregnancy rate after discontinuation of treatment exceeds 70%, but depends on the initial extent of the disease and on the severity and location of pelvic adhesions. Pseudomenopause alone has a limited value in the treatment of infertility in patients with extensive endometriosis combined with severe pelvic adhesive disease. In such patients a combined medical and surgical treatment offers advantages over each of these two approaches when applied individually. A three to six month course of danazol prior to conservative surgery facilitates surgical resection of endometriosis and limits its extent and is associated with better clinical results.