Library / Hormonal

Ganirelix

Also known as Orgalutran, Fyremadel

Approved medicine

Gonadotrophin releasing hormone antagonist decapeptide. Approved to prevent premature LH surges during IVF stimulation.

Prescription medicine. Only a prescriber can decide whether a medicine suits you and at what dose. This page is information, not a recommendation.

Background

Synthetic decapeptide made by substituting six amino acids in natural gonadotrophin releasing hormone (GnRH) so that it blocks rather than stimulates the GnRH receptor. First approved by the US FDA in July 1999 (Organon), with generic versions since.

How it is thought to work

Competitively blocks GnRH receptors in the pituitary, causing a rapid and reversible fall in luteinising hormone (LH) and follicle stimulating hormone (FSH). In IVF this stops an early LH surge from releasing eggs before they can be collected.

What is claimed, and the evidence

Claim	Evidence	Notes
Preventing premature LH surges in women having controlled ovarian stimulation for IVF	Approved use	FDA label indication, based on two randomised controlled studies; a premature surge occurred in under 1% of 463 women given the approved dose.

Side effects

Effect	How often	Notes
Abdominal or pelvic pain	Common	Gynaecological abdominal pain in 4.8% of treated women in the label trials.
Headache	Common	3.0% in label trials.
Ovarian hyperstimulation syndrome Serious	Common	2.4% in label trials, during combined stimulation with FSH; can cause fluid shifts, clots and hospitalisation.
Vaginal bleeding	Uncommon	1.8% in label trials.
Injection site reaction	Uncommon	1.1% in label trials.
Nausea	Uncommon	1.1% in label trials.
Pregnancy loss Serious	Common	Fetal death reported in 3.7% of treated women in label trials, recorded without regard to cause; reflects IVF pregnancies generally.
Hypersensitivity reactions including anaphylaxis, angioedema and hives Serious	Rare	Post marketing reports, sometimes after the first dose.

Warnings

Contraindicated in known or suspected pregnancy.
Serious allergic reactions, including anaphylaxis, have been reported as early as the first dose; some syringe needle shields contain natural rubber latex.
Used only within supervised fertility treatment alongside gonadotrophins and ultrasound monitoring.

Regulatory status

Australia: Approved (ARTG, ganirelix products).
United States: FDA approved (1999; generic versions) to prevent premature ovulation during ovarian stimulation.

Sources

Also in Hormonal

From the VialOwl library, reviewed 26 September 2026. For education and general information. It is not medical advice and not a recommendation to use Ganirelix.