Pharmacotherapeutic Group: Progestogen. ATC Code: G: Genitourinary system and sex hormones.
Pharmacology: Pharmacodynamics: Compensates for progesterone deficiency. The affinity of Lutenyl for progesterone receptors is 2.5 higher than the natural hormone.
Lutenyl has no androgenic, anabolic, estrogenic, corticoadrenal or anti-inflammatory activity and therefore does not interfere with glucose metabolism, nor with water or electrolyte balance, and does not affect bromo-sulfophthalein (BSP) clearance.
When administered from the 5th-25th day at the usual dose of 5 mg daily, Lutenyl suppresses the ovulatory peak of gonadotropins, lowers circulating estrogen concentration and prevents secretion of progesterone. Pharmacoclinical studies have not shown a complete antigonadotropic effect in all patients.
Pharmacokinetics: The pharmacokinetic study conducted after administration of a single dose shows that: Absorption into the digestive tract is rapid, with peak plasma level being reached within 2 hrs, half-life is about 40 hrs. Nomegestrol acetate binds at a high rate (96.8±0.8%) as does progesterone (97.2-97.6%), to plasma albumin. It does not bind to sex hormone-binding globulin (SHBG) nor to corticosteroid-binding globulin (CBG).
As with other progesterone derivatives, the principal metabolites are hydroxylated. They are partially (glucurono- and sulpho-) conjugated and eliminated mainly by the intestinal route, and partly in the urine.
No accumulation of nomegestrol acetate occurred after daily administration of a tablet containing 5 mg.
A single daily dose of Lutenyl is justified by its good bioavailability after oral administration and by its long half-life.