PRELIMINARY-REPORT ON THE TREATMENT OF ENDOMETRIOSIS WITH LOW-DOSE MIFEPRISTONE (RU-486)

OBJECTIVE: We have previously shown that treatment with mifepristone, 50 to 100 mg daily, results in amenorrhea, anovulation, and symptomati c improvement in women with endometriosis. In this study we lowered th e dose to 5 mg daily to determine whether clinical efficacy is altered without other adverse actions. STUDY DESIGN: After a baseline cycle, seven women with endometriosis were given mifepristone, 5 mg daily, fo r 6 months. Daily symptom inventories were recorded. Laparoscopy was p erformed during the sixth month of therapy. RESULTS: Pelvic pain impro ved in six of seven patients. Cyclic bleeding ceased in all patients, but four of the seven patients complained of irregular bleeding. Surgi cal staging at the conclusion of the study (five of seven patients) di d not detect a change in endometriosis. CONCLUSIONS: Mifepristone, 5 m g daily, resulted in symptomatic improvement, but did not stabilize th e endometrium. From our experience with three doses of mifepristone, w e would recommend a dose of 50 mg be used for continued investigations .