Medical treatment of endometriosis: a comparison of the suppressive effects of danazol and nafarelin on reproductive hormones

Abstract

Patients with endometriosis were studied to investigate hormonal suppression by the gonadotropin-releasing hormone against nafarelin acetate compared with danazol. We hypothesized that the pattern, time course, and degree of gonadotropin and ovarian suppression would be different. The study included 16 patients who were randomized into one of three 6-month treatment protocols. Patients were recruited from a university hospital setting. Eligible candidates were 18 to 45 years of age, with regular menses and documented pelvic endometriosis. Six-month treatment protocols included nafarelin 800 or 400 micrograms/d, or danazol 800 mg/d. Serum estradiol (E2), progesterone (P), luteinizing hormone (LH), and follicle-stimulating hormone were determined before treatment and then monthly. Thirteen patients consented to a 12-hour hospital admission during the 5th and 6th month of treatment to determine LH pulse frequency and amplitude. Estradiol and P were suppressed in all groups, but E2 significantly more by nafarelin than danazol (P less than or equal to 0.01). Nafarelin, 800 micrograms, significantly depressed LH pulse amplitude compared with danazol (P less than or equal to 0.05). Two patients in the nafarelin group had the administration of their medication observed, and both demonstrated single, high-amplitude pulses immediately after administration. Nafarelin is a more potent LH and E2 suppressor than danazol, and the agonist effect of nafarelin may continue to provoke transient gonadotropin responses despite long-term therapeutic suppression.