Cetrorelix
GnRH analogues (agonists and antagonists)
GnRH analogues (agonists and antagonists)Pregnancy: contraindicated
Contraindicated in pregnancy and breastfeeding: in animals it caused fetal loss, consistent with its anti-gonadotropin action.
Injected GnRH antagonist peptide used in IVF to stop a premature LH surge. Given under the skin of the lower abdomen; rare severe allergy.
Quick facts
- Group
- GnRH analogues (agonists and antagonists)
- Target
- Gonadotropin-releasing hormone receptor (GnRH-R) on pituitary gonadotroph cells
- Used for
- Prevention of premature LH surges
- Key effects
- Reddening · Nausea and headache
- Monitor
- Pregnancy excluded before starting · Signs of allergy
- ATC
- H01CC02
No doses: the clinician sets them by the current guideline.
Mechanism of action
Cetrorelix is a synthetic decapeptide related to natural GnRH, with several amino acids replaced. It competitively blocks GnRH receptors on the pituitary, so LH (and less so FSH) falls rapidly, with no initial surge of gonadotropins. In ovarian stimulation for assisted reproduction, this stops the premature LH surge that would make the follicles ovulate before the eggs are collected. The effect wears off quickly when the drug is stopped.
- The antagonist blocks GnRH receptors in the pituitary
- LH falls rapidly, with no initial flare
- No premature LH surge: follicles wait for egg retrieval
Indications
- Prevention of premature LH surges in women undergoing controlled ovarian stimulation. Female infertility →
Adverse effects
Common
- Reddening, itching and swelling at the injection site
- Nausea and headache
- Mild rise in liver enzymes
Contraindications
- Known or suspected pregnancy, and breastfeeding
- Allergy to cetrorelix, to extrinsic peptide hormones, to mannitol, or to GnRH or its analogues
- Severe kidney impairment
Key interactions
- Other medicines
- No formal interaction studies exist; it had no notable effect on other hormone levels during stimulation, apart from blocking the LH surge.
What is monitored
- Pregnancy excluded before starting
- Follicle growth and hormone levels, as part of the stimulation cycle
- Signs of allergy, especially in women with allergic conditions
Administration and safety
- Powder reconstituted with sterile water and injected under the skin.
- Injected in the lower abdomen around the navel, keeping away from the navel itself; the site is changed each day.
- May be self-injected after training, following the patient leaflet.
- Prescribed by a specialist experienced in fertility treatment.
Pregnancy and breastfeeding
Contraindicated in pregnancy and breastfeeding: in animals it caused fetal loss, consistent with its anti-gonadotropin action.
Nursing care
- Confirm that pregnancy has been excluded.
- Ask about allergies and allergic conditions; it is not advised in severe allergic disease.
- Teach reconstitution, injection technique and daily site change.
- Teach the signs of ovarian hyperstimulation and of a severe allergic reaction.
Pharmacokinetics
- Absorption
- Subcutaneous injection after the powder is mixed with sterile water.
- Half-life
- Hours after a single injection, longer with repeated doses; it varies widely.
Test yourself
Think of the answer, then tap the question to see it.
Which kidney condition is a contraindication to cetrorelix?
Severe kidney impairment.
Which excipient allergy is a contraindication to cetrorelix?
Mannitol.
Why does cetrorelix suppress LH faster than leuprorelin at the start?
It blocks the GnRH receptor directly instead of first stimulating it, so there is no initial flare.
Connections
← Back to the class: GnRH analogues (agonists and antagonists)
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - CETRORELIX ACETATE kit (DailyMed (U.S. National Library of Medicine), 2024); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.