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Hormones & reproductionGnRH antagonist

Ganirelix

Also known as: Ganirelix acetate, Fyremadel, Antagon, Orgalutran, Org 37462

By the Peptide Dossier Editorial TeamUpdated How we source

Ganirelix is a Gn RH receptor antagonist used during controlled ovarian stimulation to prevent a premature LH surge. It is a cycle-specific assisted-reproduction medicine, not ongoing hormone suppression.

Quick Facts

Class:Gn RH antagonist
US product context:FDA-approved for preventing premature LH surges during controlled ovarian stimulation.
Evidence context:Phase III assisted-reproduction evidence supports comparable pregnancy outcomes with a shorter antagonist protocol.

Identity and product names

Ganirelix acetate is a synthetic ten-amino-acid Gn RH antagonist developed asOrg 37462 by Organon. Original US approval was in 1999 as Antagon. Current US names include ganirelix acetate injection and Fyremadel; Orgalutran is used in some other regions.

Sources: [1]

Pituitary blockade during IVF

Competitive pituitary Gn RH-receptor blockade rapidly and reversibly suppresses LH and FSH. During ovarian stimulation, holding down an early LH surge prevents premature ovulation before follicles are ready for planned egg retrieval.

Unlike older agonist protocols requiring longer pituitary suppression, the antagonist allows a shorter flexible course. A North American Phase III comparison with long leuprolide found comparable ongoing pregnancy rates, fewer injections and fewer injection-site reactions.

Sources: [2]

Approved dose and clinical use

FDA approved ganirelix in 1999. The described regimen is 0.25 mg subcutaneously once daily during controlled ovarian stimulation to inhibit premature LH surges. It is used only during that stimulation phase, not continuously. Antagon is no longer the US brand; current product-specific instructions remain relevant.

Sources: [3], [4]

Common effects include injection-site reactions, headache, nausea and abdominal/pelvic discomfort. Hypersensitivity is an important risk. Ovarian hyperstimulation syndrome relates to the overall stimulation cycle rather than ganirelix alone. Pregnancy is a contraindication.

References and further reading

This reference draws on Superpower’s Peptide Library and the research linked below. Peptide Dossier’s editorial team adapted and integrated the material on .

  1. drugs.comIdentity and product namesCited in: Identity and product names
  2. 10.1016/s0015-0282(00)01638-1Pituitary blockade during IVFCited in: Pituitary blockade during IVF
  3. organonpro.comApproved dose and clinical useCited in: Approved dose and clinical use
  4. organon.comApproved dose and clinical useCited in: Approved dose and clinical use

Frequently Asked Questions About Ganirelix

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Disclaimer: This article is for informational and educational purposes only. It is not intended as medical advice. The information presented is based on published research and should not be used as a substitute for professional medical guidance. Always consult a qualified healthcare provider before starting any peptide protocol. Some peptides discussed may not be approved for human use by the FDA or equivalent regulatory bodies.