Safety and effectiveness of different dosage of mifepristone for the treatment of uterine fibroids: a double-blind randomized clinical trial

OBJECTIVES The aim of this study was to evaluate the safety and improvement in quality of life using 10 mg and 5 mg daily doses of mifepristone for the treatment of uterine fibroids. DESIGN The research was a randomized double-blind clinical study undertaken at the Eusebio Hernández Hospital in Havana, Cuba. SUBJECTS AND METHODS Seventy subjects with symptomatic uterine fibroids took one daily capsule of 10 mg or 5 mg mifepristone orally for 9 months. One to three endometrial biopsies were performed. In evaluating safety, the variables studied were endometrial changes associated with mifepristone, elevation of hepatic transaminases, side effects of mifepristone, and instances and duration of irregular bleeding. RESULTS There were 30/49 (61.2%) and 13/24 (54.2%) diagnoses of endometrial changes associated with mifepristone in the 10 mg and 5 mg groups, respectively (P = 0.282). At every evaluation visit the average endometrial thickness was significantly greater in the 10 mg group than in the 5 mg group (P = 0.013, P = 0.002, and P = 0.013, respectively). Only five subjects had slight elevations in their hepatic transaminases after 9 months' treatment. Sixteen of 35 (45.7%) and eight of 33 (24.2%) subjects had the occasional hot flush in the 10 mg and 5 mg groups, respectively (P = 0.032). In total, there were 12.9 ± 4.6 (n = 21) and 9.1 ± 3.9 (n = 18) days of irregular bleeding in the 10 mg and 5 mg groups, respectively (P = 0.009). CONCLUSION According to the study findings, a 5 mg daily dose over 9 months has a relatively better safety profile than the 10 mg dose.