Promegestone, sold under the brand name Surgestone, is a progestin medication which is used in menopausal hormone therapy and in the treatment of gynecological disorders.

[6][12] In addition to its use as a medication, promegestone has been widely used in scientific research as a radioligand of the progesterone receptor.

[14] Promegestone tablets have a contraceptive effect and are used as a form of progestogen-only birth control, although it is not specifically licensed as such.

[8][2] In addition, promegestone has been found to possess some neurosteroid activity by acting as a non-competitive antagonist of the nicotinic acetylcholine receptor, similarly to progesterone.

[16] Following oral administration, peak serum levels of promegestone are reached after 1 to 2 hours.

[18] The medication is stereoselectively metabolized into trimegestone, the 21(S)-hydroxy metabolite, which is the main compound found in plasma; it circulates at levels approximately twice those of promegestone itself.

[7][19] A second metabolite, 21(R)-hydroxypromegestone, circulates at far lower concentrations (AUCTooltip area-under-the-curve levels ratio for the (S)- and (R)-isomers of about 21).

[5] Promegestone is the generic name of the drug and its INNTooltip International Nonproprietary Name, while promégestone is its DCFTooltip Dénomination Commune Française.