Lynestrenol Pharmacology

Lynestrenol itself does not bind to the progesterone receptor and is abeyant as a progestogen. It is a prodrug, and aloft articulate administration, is rapidly and about absolutely adapted into norethisterone, a almighty progestogen, in the alarmist during first-pass metabolism. No added metabolites besides norethisterone are formed from lynestrenol. As such, its pharmacological action is about identical to that of norethisterone. The about-face of lynestrenol into norethisterone is catalyzed by CYP2C9 (28.0%), CYP2C19 (49.8%), and CYP3A4 (20.4%), while added cytochrome P450 enzymes are anniversary amenable for no added than 1.0% of the absolute conversion. It appears that lynestrenol aboriginal undergoes hydroxylation of the C3 position, basic etynodiol as an intermediate, followed by oxygenation of the hydroxyl accumulation to anatomy norethisterone.

The aiguille claret are accomplished aural 2 to 4 hours afterwards articulate administration, 97% of the administered dosage getting apprenticed to claret proteins. Lynestrenol and its metabolites are predominantly excreted in the urine, beneath through feces, alive metabolite norethisterone abolishment half-life getting 16 to 17 hours.