ChEBI: Mifepristone is a 3-oxo-Delta(4) steroid, an acetylenic compound and a tertiary amino compound. It has a role as an abortifacient, a contraceptive drug, a synthetic oral contraceptive and a hormone antagonist. It derives from a hydride of an estrane.NCI Thesaurus (NCIt): Mifepristone is a derivative of the synthetic progestin norethindrone with antiprogesterone activity. Mifepristone competitively binds to the progesterone receptor, resulting in inhibition of the effects of endogenous or exogenous progesterone. This agent also exhibits antiglucocorticoid and weak antiandrogenic activities. ChEBI: Mifepristone is a 3-oxo-Delta(4) steroid, an acetylenic compound and a tertiary amino compound. It has a role as an abortifacient, a contraceptive drug, a synthetic oral contraceptive and a hormone antagonist. It derives from a hydride of an estrane.