[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [GnRH analogues (agonists and antagonists)](https://durgical.com/en/pharmacology/classes/gnrh-analogues/) › Cetrorelix

# 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.

Updated Nov 1, 2026

## Quick facts

**Group**
[GnRH analogues (agonists and antagonists)](https://durgical.com/en/pharmacology/classes/gnrh-analogues/)

**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.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Clinical What the labels mean

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## 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 →](https://durgical.com/en/conditions/female-infertility/)

## Adverse effects

### Common

- Reddening, itching and swelling at the injection site
- Nausea and headache
- Mild rise in liver enzymes

### Serious (rare, important)

- Ovarian hyperstimulation syndrome (from the stimulation regimen)
- Allergic and anaphylactoid reactions, sometimes with the first dose

## 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.

## Memory aid

CETrorelix CUTS the LH surge: a daily shot in the lower belly during IVF stimulation — check the allergy history first.

## 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.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/cetrorelix/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## What the labels mean

**Pregnancy: contraindicated**
Contraindicated in pregnancy and breastfeeding: in animals it caused fetal loss, consistent with its anti-gonadotropin action.

## Connections

## Related drugs 3

- [Ganirelix](https://durgical.com/en/pharmacology/ganirelix/)
- [Degarelix](https://durgical.com/en/pharmacology/degarelix/)
- [Leuprorelin](https://durgical.com/en/pharmacology/leuprorelin/)

## Related conditions 1

- [Female infertility](https://durgical.com/en/conditions/female-infertility/)

[← Back to the class: GnRH analogues (agonists and antagonists)](https://durgical.com/en/pharmacology/classes/gnrh-analogues/)

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](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c9c50fcb-b28d-4085-9116-b38a21d31b99) (DailyMed (U.S. National Library of Medicine), 2024); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=H01CC02) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/pharmacology/cetrorelix/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/cetrorelix/