indication

For the inhibition of premature LH surges in women undergoing controlled ovarian stimulation

pharmacology

Cetrorelix is a synthetic decapeptide with gonadotropin-releasing hormone (GnRH) antagonistic activity. GnRH induces the production and release of luteinizing hormone (LH) and follicle stimulating hormone (FSH) from the gonadotrophic cells of the anterior pituitary. Due to a positive estradiol (E2) feedback at midcycle, GnRH liberation is enhanced resulting in an LH-surge. This LH-surge induces the ovulation of the dominant follicle, resumption of oocyte meiosis and subsequently luteinization as indicated by rising progesterone levels. Cetrorelix competes with natural GnRH for binding to membrane receptors on pituitary cells and thus controls the release of LH and FSH in a dose-dependent manner.

mechanism of action

Cetrorelix binds to the gonadotropin releasing hormone receptor and acts as a potent inhibitor of gonadotropin secretion. It competes with natural GnRH for binding to membrane receptors on pituitary cells and thus controls the release of LH and FSH in a dose-dependent manner.

biotransformation

In in vitro studies, cetrorelix was stable against phase I- and phase II-metabolism. Cetrorelix was transformed by peptidases, and the (1-4) peptide was the predominant metabolite.

absorption

Rapidly absorbed following subcutaneous injection. The mean absolute bioavailability following subcutaneous administration to healthy female subjects is 85%.

half life

~62.8 hours

route of elimination

Following subcutaneous administration of 10 mg cetrorelix to males and females, only unchanged cetrorelix was detected in urine.