Mifepristone: current knowledge and emerging prospects.

The first clinically available antiprogestin, mifepristone has generated immense interest in the research community since its' discovery in 1980. Mifepristone is a synthetic orally active steroid with potent antiglucocorticoid, antiprogestogen and a weak anti-androgen activity, used primarily for termination of pregnancy. It acts as a competitive receptor antagonist at the progesterone receptor in the presence of progesterone, and acts as a partial agonist in the absence of progesterone. Extensive research has been carried out regarding its' antiprogestogen activity for use in medical abortion. Lately other medical uses of mifepristone are being explored like for induction of labour in late preg- nancy, as oestrogen free oral contraceptive and for treatment of endometriosis, uterine fibroids, ovarian cancer, prostate cancer, meningiomas, Cushing's syndrome and major psychotic depression.