2- Buserelin
Buserelin is a Gonadotropin-releasing hormone agonist (GnRH
agonist). The drug's effects are dependent on the frequency and time course of
administration. GnRH is released in a pulsatile fashion in the postpubertal
adult. Initial interaction of any GnRH agonist, such as buserelin, with the
GnRH receptor induces release of FSH and LH by gonadotrophes. Long-term
exposure to constant levels of buserelin, rather than endogenous pulses, leads
to downregulation of the GnRH receptors and subsequent suppression of the
pituitary release of LH and FSH.
Like other GnRH agonists, buserelin may be used in the treatment of
hormone-responsive cancers such as prostate cancer or breast cancer,
estrogen-dependent conditions (such as endometriosis or uterine fibroids), and
in assisted reproduction.
It is normally delivered via a nasal spray, but is also available
as an injection.
Buserelin acetate is marketed by Sanofi-Aventis under the brand
name Suprefact and a generic form of Buserelin is now produced by CinnaGen
under the brand name CinnaFact.
Buserelin is also marketed under the brand name Metrelef. Metrelef
is approved to treat patients with endometriosis by suppression of ovarian
hormone production. In ovulation induction Metrelef is used as a pituitary
blockade as an adjunct to gonadotrophin administration.
