Last reviewed 2026-04-22 · How we verify

Antagon ™

Antagon is a gonadotropin-releasing hormone (GnRH) antagonist that rapidly suppresses luteinizing hormone (LH) and follicle-stimulating hormone (FSH) to prevent premature ovulation during assisted reproductive technology.

Antagon is a gonadotropin-releasing hormone (GnRH) antagonist that rapidly suppresses luteinizing hormone (LH) and follicle-stimulating hormone (FSH) to prevent premature ovulation during assisted reproductive technology. Used for Prevention of premature luteinizing hormone surge in women undergoing controlled ovarian hyperstimulation for assisted reproductive technology (ART).

At a glance

Mechanism of action

Antagon binds competitively to GnRH receptors on pituitary gonadotroph cells, causing immediate and reversible suppression of gonadotropin secretion. This prevents the endogenous LH surge that would otherwise trigger premature ovulation during controlled ovarian hyperstimulation in fertility treatment cycles.

Approved indications

• Prevention of premature luteinizing hormone surge in women undergoing controlled ovarian hyperstimulation for assisted reproductive technology (ART)

Common side effects

• Headache
• Ovarian hyperstimulation syndrome (OHSS)
• Abdominal pain
• Nausea
• Injection site reactions

Key clinical trials

• A Study to Compare the Safety and Efficacy of Cetrotide® 3 Milligram (mg) Versus Antagon™ in Women Undergoing Ovarian Stimulation (PHASE4)
• Oral Microdose Lupron Versus Luteal Estradiol Trial in Poor Responder In Vitro Fertilization (IVF) Patients (PHASE4)

Primary sources

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