Pharmacodynamics Trimegestone (21(S)-hydroxyl-promegestone), the major active metabolite of<unk> .<unk>  is a progestogen, or an agonist of the progesterone receptor. It has about 200% of the affinity of progesterone for the PR. The endometrial transformation dosage of<unk>  is 10 mg per cycle and its ovulation-inhibiting dosage is 0.5 mg/day.<unk>  has weak glucocorticoid activity in addition to its progestogenic activity. Conversely, it has no androgenic, estrogenic, mineralocorticoid, or other hormonal activity. It appears to possess antiandrogenic activity. Its major metabolite trimegestone has weak antimineralocorticoid and antiandrogenic activity. In addition,<unk>  has been found to possess some neurosteroid activity by acting as a non-competitive antagonist of the nicotinic acetylcholine receptor, similarly to progesterone. Pharmacokinetics Following oral administration, peak serum levels of<unk>  are reached after 1 to 2 hours. The medication is mainly bound to albumin; it does not bind to sex hormone-binding globulin, and binds only weakly to corticosteroid-binding globulin. The metabolism of<unk>  is mainly via hydroxylation at the C21 position and at other positions. Progesterone is similarly hydroxylated at the C21 position, into 11-deoxycorticosterone (21-hydroxyprogesterone). However, the C9(10) double bond of<unk>  greatly limits the A-ring reduction that progesterone undergoes, resulting in 21-hydroxylation being the main route of metabolism for<unk> . 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<unk>  itself. In addition, trimegestone has more than three-fold higher affinity for the PR than does<unk> . As such,<unk>  is largely a prodrug of trimegestone. A second metabolite, 21(R)-hydroxypromegestone, circulates at far lower concentrations ( ratio for the (S)- and (R)-isomers of about 21). The elimination half-life of trimegestone is 13.8 to 15.6 hours.<unk> , trimegestone, and 21(R)-hydroxypromegestone are not excreted in urine, while 3% of a dose is recovered as the glucuronide and/or sulfate conjugate of trimegestone and 1% of a dose is recovered as the glucuronide and/or sulfate conjugate of 21(R)-hydroxypromegestone.
Promegestone
Algestone
Algestone acetonide
Metapristone
Nomegestrol acetate
Telapristone
Gestodene
Ethinylestradiol sulfonate