Norethindrone acetate or dienogest for the treatment of symptomatic endometriosis: a before and after study.

Objective: To assess the proportion of patients satisfied with their treatment before and after a systematic change from norethindrone acetate to dienogest as the first-line progestin for symptomatic endometriosis.

Design: Before and after study.

Setting: Academic department.

Patient(s): The last 90 new consecutive endometriosis patients in whom norethindrone acetate was used, and the first 90 new consecutive endometriosis patients in whom dienogest was used.

Intervention(s): Norethindrone acetate at the oral dose of 2.5 mg once a day until June 6, 2013, then dienogest at the oral dose of 2 mg once a day thereafter.

Main Outcome Measure(s): Degree of satisfaction with treatment after 6 months of progestin therapy and assessment of any variations in pain symptoms, psychological status, sexual function, or health-related quality of life associated with the introduction of dienogest.

Result(s): The proportion of satisfied plus very satisfied women after 6 months of treatment was 71% in the "before" period (norethindrone acetate) and 72% in the "after" period (dienogest). The implementation of dienogest was not associated with statistically significant ameliorations in overall pain relief, psychological status, sexual functioning, or health-related quality of life. Treatment was well tolerated by 58% of norethindrone acetate users compared with 80% of dienogest users. After dienogest implementation, the absolute risk reduction in the occurrence of any side effect was 13.9% (95% confidence interval, 0.8%-28.6%).

Conclusion(s): Considering the large difference in the cost of the two drugs, dienogest should be suggested selectively in women who do not tolerate norethindrone acetate.