GnRH antagonist injection
Orgalutran
Also known as Ganirelix
Orgalutran is a GnRH antagonist given by injection under the skin, working in a similar way to Cetrotide by blocking the hormone signal that would otherwise cause early ovulation.
Why it may be used
It is used during IVF stimulation to stop eggs being released before the clinic is ready to carry out egg retrieval.
Where it fits in a cycle
It is usually started partway through the stimulation phase, once follicles reach a certain size, and continues until the trigger injection, as part of an antagonist protocol.
Side effects listed in the patient leaflet
- Injection site redness or irritation
- Headache
- Nausea
- Abdominal discomfort
- Fatigue
- Ovarian enlargement during treatment
When to ring the clinic
- •Rapid or severe abdominal swelling
- •Severe abdominal or pelvic pain
- •Breathlessness
- •A marked reduction in urine output
- •Signs of infection at the injection site, or an allergic reaction such as widespread rash or swelling of the face
Questions people ask
- Is Orgalutran given as a pre-filled syringe?
- It is commonly supplied as a pre-filled syringe, but confirm the exact device and technique with your clinic nurse.
- What if a dose is missed?
- Contact your clinic promptly rather than adjusting the schedule yourself.
- Does it need refrigeration?
- Check the patient information leaflet for storage instructions specific to this product.
- Can it be combined with Gonal-F or Menopur?
- It is commonly used alongside an FSH medicine in an antagonist protocol, but only follow the combination your clinic has prescribed for you.
Safety
- This is general information only and does not replace advice from your clinical team.
- Follow the exact schedule set out by your own clinic.
- The patient information leaflet in the box is the authoritative reference for this medicine.
- Tell your clinic about other medicines, allergies and medical conditions before starting.
Read next
Sources
- Patient information leaflets and product characteristics, electronic medicines compendium (emc). Link checked 17 September 2026.
- IVF: what is IVF and how does it work?, HFEA (UK fertility regulator). Link checked 17 September 2026.
Written by patients, not clinicians. This page has not yet been reviewed by a named fertility professional, so it explains published guidance and points you to the original source instead of giving medical advice. It is not medical advice. Decisions about your treatment belong with your own clinic. Read our editorial policy and corrections policy.