Epostane
Epostane is an inhibitor of 3β-hydroxysteroid dehydrogenase that was developed as a contraceptive, abortifacient, and oxytocic drug but was never marketed. By inhibiting 3β-HSD, epostane blocks the biosynthesis of progesterone from pregnenolone, thereby functioning as an antiprogestogen and terminating pregnancy. The drug was trialed and in a study was found to be slightly more effective at inducing abortion relative to mifepristone.
