Abstract

PIP: This monograph review on medroxyprogesterone acetate (MPA) includes chemical and physical data (synonyms and trade names), structural and molecular formulae and molecular weight, chemical and physical properties of MPA, and the production, use, occurrence, and analysis of MPA. Production of MPA, which is not known to occur naturally, can be accomplished by 4 main chemical reactions, and several patents for synthesis routes have been issued; these reactions are summarized. MPA is used orally for treatment of secondary amenorrhea and dysfunctional uterine bleeding in the U.S. It is also administered for treatment of endometriosis. Other countries use MPA as an injectable contraceptive, and Japan uses it in treatment of threatened abortion. MPA also has various veterinary uses. Typical analytical methods for determining MPA purity and chemical clarity are outlined tabularly. Biological data relevant to the evaluation of carcinogenic risk to humans of MPA are also presented. In experimental animals (mice and dogs), MPA produced mammary tumors in dogs when injected intramuscularly. MPA is also reported to have teratogenic effects in some animal species. Human data consist of 1 epidemiological study on breast nodule development and 2 studies of the development of dysplasias and carcinoma in situ of the cervix. These studies have conflicting results and methodological problems, but it is concluded that there is limited evidence for the carcinogenicity of MPA in dogs. No conclusions can be made about its carcinogenicity for humans based on the extant studies.