Progestins for Symptomatic Endometriosis: Results of Clinical Studies

Progestins, which are synthetic progestational compounds, have been used in the management of symptomatic endometriosis, both as primary therapy and as an adjunct to surgery. Several oral compounds have been used for this purpose, and different degrees of benefits have been shown. The lack of a standardized instrument to evaluate painful symptoms makes comparative analysis very difficult. We performed a systematic search of the Pubmed database from January 1980 to January 2015. The database used the term "endometriosis" as the relevant medical subject heading; selected sub-headings were "progestins", "medical therapy", "review" and "randomized controlled trials", "controlled trials", "case-control studies", and "descriptive studies". We aimed to review all available trials in order to investigate the medical treatment of endometriosis solely with progestins, with special attention to pharmacodynamic activity. The drugs studied were cyproterone acetate, norethisterone acetate, medroxyprogesterone acetate, levonorgestrel, etonogestrel, dienogest, and selective progesterone receptor modulators. However, it is very difficult to reach a definitive conclusion because most trials were small, retrospective, and uncontrolled. Nevertheless, it is clear that progestins are generally safe, effective, and well tolerated and should be considered as the first line of medical treatment in symptomatic endometriosis provided the patients have no desire for pregnancy.