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Cetrorelix (injectable)

Generic name: cetrorelix (injectable) [ SE-troe-REL-ix ]
Brand name: Cetrotide
Dosage form: subcutaneous powder for injection (0.25 mg; 3 mg)
Drug class: Gonadotropin-releasing hormone antagonists

Medically reviewed by on Jan 12, 2023. Written by Cerner Multum.

What is cetrorelix?

Cetrorelix is a man-made form of a protein that blocks the effects of certain hormones in the body that control ovulation (release of an egg from the ovary). If ovulation occurs too soon during fertility treatment, the eggs may not be suitable for fertilization. Cetrorelix works by preventing eggs from being released too early (premature ovulation).

Cetrorelix is used to prevent premature ovulation during controlled ovarian stimulation.

Cetrorelix may also be used for purposes not listed in this medication guide.


You should not use cetrorelix if you have severe kidney disease, if you are pregnant or breast-feeding, or if you have ever had an allergic reaction to a medicine similar to cetrorelix (such as Lupron, Antagon, Zoladex, Synarel, Zoladex, or others).

Before taking this medicine

You should not use cetrorelix if you are allergic to it, or if:

  • you have severe kidney disease;

  • you are pregnant;

  • you are breast-feeding a baby;

  • you are allergic to mannitol; or

  • you have had an allergic reaction to other gonadotropin-releasing hormone medications (such as Lupron, Antagon, Zoladex, Synarel, Zoladex, or others).

Using cetrorelix if you are already pregnant can cause birth defects, miscarriage, or stillbirth. Do not use if you are pregnant. You may need to have a negative pregnancy test before starting this treatment.

It is not known whether cetrorelix passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using cetrorelix.

To make sure cetrorelix is safe for you, tell your doctor if you have:

How should I use cetrorelix?

Follow all directions on your prescription label. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Cetrorelix is injected under the skin. You may be shown how to use injections at home. Do not give yourself this medicine if you do not understand how to use the injection and properly dispose of used needles and syringes.

Cetrorelix is a powder medicine that must be mixed with a liquid (diluent) before using it. If you are using the injections at home, be sure you understand how to properly mix and store the medicine.

Your care provider will show you the best places on your body to inject cetrorelix. Use a different place each time you give an injection. Do not inject into the same place two times in a row.

Read all patient information, medication guides, and instruction sheets provided to you. Ask your doctor or pharmacist if you have any questions.

For best results, you will need to start using cetrorelix injections on a certain day of your cycle. Follow your doctor's dosing instructions about when to use this medicine, and at what time of day to give your injections.

As part of your fertility treatment, you will be treated with a second medicine called human chorionic gonadotropin (hCG). You will receive an hCG injection only on days when your ovaries are ready for controlled ovulation to occur.

You will need frequent ultrasound examinations to check your ovaries for signs of readiness for ovulation. This will help your doctor determine when to give your hCG injection.

Store cetrorelix in a refrigerator. Do not freeze. Keep the medicine in its original carton to protect it from light. Throw away any medicine not used before the expiration date on the medicine label.

Use a disposable needle and syringe only once. Follow any state or local laws about throwing away used needles and syringes. Use a puncture-proof "sharps" disposal container (ask your pharmacist where to get one and how to throw it away). Keep this container out of the reach of children and pets.

What happens if I miss a dose?

Call your doctor for instructions if you miss a dose of cetrorelix.

Try not to miss any doses. The timing of your injections is very important to the success of your fertility treatments.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

An overdose of cetrorelix is not expected to produce life threatening symptoms.

What should I avoid while using cetrorelix?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Cetrorelix side effects

Get emergency medical help if you have signs of an allergic reaction: hives or rash; cough, difficult breathing; feeling light-headed; swelling of your face, lips, tongue, or throat.

Some women using cetrorelix develop a condition called ovarian hyperstimulation syndrome (OHSS), especially after the first treatment. OHSS can be a life threatening condition.

Call your doctor right away if you have any of the following symptoms of OHSS:

  • stomach pain, bloating;

  • nausea, vomiting, diarrhea;

  • rapid weight gain, especially in your face and midsection;

  • little or no urination; or

  • pain when you breathe, rapid heart rate, feeling short of breath (especially when lying down).

Common side effects of cetrorelix may include:

  • nausea;

  • headache; or

  • redness, bruising, itching, or swelling where the medicine was injected.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Cetrorelix dosing information

Usual Adult Dose for Ovulation Induction:

0.25 mg subcutaneously on either stimulation day 5 (morning or evening) or day 6 (morning) and continuing daily until the day of human chorionic gonadotropin (HCG) administration

-This drug is for subcutaneous injection into the lower abdominal wall.
-When assessment by ultrasound shows a sufficient number of follicles of adequate size, HCG is administered to induce ovulation and final maturation of the oocytes. No HCG should be administered if the ovaries show an excessive response to the treatment with gonadotropins to reduce the chance of developing ovarian hyperstimulation syndrome (OHSS).

Use: For the inhibition of premature luteinizing hormone (LH) surges in women undergoing controlled ovarian stimulation

What other drugs will affect cetrorelix?

Other drugs may interact with cetrorelix, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.