Title: Ganirelix
CAS Registry Number: 124904-93-4
CAS Name: N-Acetyl-3-(2-naphthalenyl)-D-alanyl-4-chloro-D-phenylalanyl-3-(3-pyridinyl)-D-alanyl-L-seryl-L-tyrosyl-N6-[bis(ethylamino)methylene]-D-lysyl-L-leucyl-N6-[bis(ethylamino)methylene]-L-lysyl-L-prolyl-D-alaninamide
Additional Names: [N-Ac-D-Nal(2)1-D-pCl-Phe2-D-Pal(3)3-D-hArg(Et2)6-hArg(Et2)8-D-Ala10]GnRH
Molecular Formula: C80H113ClN18O13
Molecular Weight: 1570.32
Percent Composition: C 61.19%, H 7.25%, Cl 2.26%, N 16.06%, O 13.25%
Literature References: Decapeptide LH-RH antagonist. Prepn and structure-activity studies: J. J. Nestor, Jr. et al. in Peptides 1988: Proc. 20th Eur. Peptide Symp., G. Jung, E. Bayer, Eds. (Walter de Gruyter, Berlin, 1989) pp 592-594; eidem, J. Med. Chem. 35, 3942 (1992). Improved synthesis: H. B. Arzeno et al., Int. J. Pept. Protein Res. 41, 342 (1993). Degradation in aq soln: R. G. Strickley et al., Pharm. Res. 7, 530 (1990). Clinical pharmacology and pharmacokinetics: J. Rabinovici et al., J. Clin. Endocrinol. Metab. 75, 1220 (1992). Clinical trial in assisted fertilization: P. Devroey et al., Hum. Reprod. 13, 3023 (1998).
Derivative Type: Acetate
CAS Registry Number: 129311-55-3
Manufacturers' Codes: Org-37462; RS-26306
Trademarks: Antagon (Organon); Orgalutran (Organon)
Molecular Formula: C80H113ClN18O13.2C2H4O2
Molecular Weight: 1690.42
Percent Composition: C 59.68%, H 7.21%, Cl 2.10%, N 14.91%, O 16.09%
Properties: pKa: 4.2 (3-pyridinylalanine); 9.8 (tyrosine). Sol in water.
pKa: pKa: 4.2 (3-pyridinylalanine); 9.8 (tyrosine)
Therap-Cat: In treatment of infertility.
Keywords: LH-RH Antagonist.
Gardenins Gardinol Type Detergents Gardol? Garenoxacin Garlic

Systematic (IUPAC) name
Clinical data
AHFS/ monograph
Pregnancy cat. X (US)
Legal status -only (US)
Routes Subcutaneous injection
Pharmacokinetic data
Bioavailability 91.1%
Protein binding 81.9%
Half-life 16.2 hours
Excretion Faecal / Renal (approx. 75%/22%)
CAS number 129311-55-3 N
ATC code H01CC01
PubChem CID 16186319
ChemSpider 16736620 YesY
KEGG D08010 N
Chemical data
Formula C80H113ClN18O13 
Mol. mass 1570.4 g/mol
 N (what is this?)  (verify)

Ganirelix acetate (or diacetate) is an injectable competitive gonadotropin-releasing hormone antagonist (GnRH antagonist). It is primarily used in assisted reproduction to control ovulation. The drug works by blocking the action of GnRH upon the pituitary, thus rapidly suppressing the production and action of LH and FSH. Ganirelix is used in fertility treatment to prevent premature ovulation that could result in the harvesting of eggs that are too immature to be used in procedures such as in vitro fertilisation.[1]

GnRH agonists are also sometimes used in reproductive therapy, as well as to treat disorders involving sex-steroid hormones, such as endometriosis.[2] One advantage of using GnRH antagonists is that repeated administration of GnRH agonists results in decreased levels of gonadotropins and sex steroids due to desensitization of the pituitary. This is avoided when using GnRH antagonists such as Ganirelix.[2] The success of Ganirelix in reproductive therapy has been shown to be comparable to that when using GnRH agonists.[1]

Ganirelix is derived from GnRH itself, with amino acid substitutions made at positions 1, 2, 3, 6, 8, and 10.[3]

The European Commission gave marketing authorization for Ganirelix throughout the European Union to N.V. Organon in May 2000.[1] Ganirelix is marketed by Organon International as Antagon.

Location of the hypothalamus. GnRH is released from the hypothalamus, and subsequently acts on GnRH receptors on the anterior pituitary.