Progesterone Acetate

Hydroxyprogesterone acetate (HPA) (INN) (brand name Prodox), or 17α-hydroxyprogesterone acetate (17-OHPA), also known as acetoxyprogesterone, is a synthetic, steroidal, orally-active progestin which was discovered by Upjohn in the 1950s and, in 1960, was marketed for use in veterinary medicine. It is a derivative of progesterone and the acetate ester of 17-hydroxyprogesterone, and is a parent compound of a number of progestins, including chlormadinone acetate, cyproterone acetate, medroxyprogesterone acetate, and megestrol acetate.
Hydroxyprogesterone acetate is of relatively low potency as a progestogen, which may explain its limited relative use. It is 100-fold less potent than medroxyprogesterone acetate, 400-fold less potent than chlormadinone acetate, and 1200-fold less potent than cyproterone acetate.