Cetronax^® is indicated for use in infertility treatment within Assisted Reproductive Technology (ART) protocols.

It belongs to the pharmacological class of gonadotropin-releasing hormone (GnRH) antagonists and acts by inhibiting luteinizing hormone-releasing hormone (LHRH), thereby preventing premature ovulation during the menstrual cycle. Once the oocytes are ready for retrieval, ovulation-inducing agents are administered to trigger their release.

Cetronax^® is used in controlled ovarian stimulation protocols for infertility treatment by suppressing the premature surge of luteinizing hormone (LH).

Lyophilized powder containing 250 micrograms of cetrorelix acetate for preparation of solution for injection.

1. Wash and dry your hands thoroughly with soap and water.
2. Remove the plastic cap of the vial and disinfect the rubber stopper with an alcohol swab.
3. Using a syringe fitted with a yellow needle (20G, suitable for withdrawal), inject 1 mL of sterile water for injection through the center of the rubber stopper into the vial.
4. Without withdrawing the needle, place the vial on a flat surface and gently swirl until a clear solution is formed.
5. Do not shake vigorously. If bubbles form, allow them to dissipate.
6. Invert the vial while keeping the needle inside and withdraw the entire solution into the syringe, then remove the needle from the vial.
7. Replace the needle with a gray needle (27G, suitable for subcutaneous injection). Hold the syringe upright and gently tap to remove any air bubbles.
8. Press the plunger until a small drop appears at the needle tip, indicating readiness for injection.
9. Proceed with administration according to the injection instructions below.

Cetronax^® is administered once daily either in the morning or evening starting on day 5 of the stimulation cycle, or on the morning of day 6, after initiation of ovarian stimulation, and continued until the day of ovulation triggering. The dosing regimen may be adjusted by the physician based on the patient’s condition, ovarian response, concomitant medications, and other clinical factors.

Cetronax^® is administered subcutaneously once daily, typically in the abdominal area at least 3 cm away from the navel. To reduce local irritation, the injection site should be rotated daily. The injection site should not be painful, bruised, red, or otherwise irritated.

1. Clean the injection site with an alcohol swab and allow it to dry.
2. Gently pinch the skin at the injection site with one hand.
3. Insert the needle at a 90° angle (45° in very thin patients).
4. Inject the full content of the syringe.
5. Count to three before releasing the skin.
6. Withdraw the needle while applying gentle pressure with an alcohol swab.

Note: Syringes, needles, vials, and sterile water provided in the Cetronax^® package are for single use only. Dispose of all materials appropriately after use.

If a dose of Cetronax^® is missed, consult your physician.

In case of administration of a higher-than-recommended dose, inform your physician immediately.

Monitoring of follicular development by ultrasound examination.

Cetronax^® is contraindicated in patients with:

• History of severe, life-threatening hypersensitivity to cetrorelix acetate or any component of the formulation
• History of severe hypersensitivity to exogenous peptide hormones, gonadotropin-releasing hormone (GnRH), or other hormonally active agents with similar structures
• Moderate to severe renal or hepatic impairment
• Pregnancy or breastfeeding

In case of signs of hypersensitivity reactions, including urticaria, itching, skin redness, swelling or blistering, wheezing, chest or throat tightness, difficulty in breathing, swallowing, or speaking, unusual hoarseness, or swelling of the mouth, face, lips, tongue, or throat, seek immediate medical attention.

Use of cetrorelix acetate is contraindicated during pregnancy and breastfeeding.

Like all medicines, Cetronax^® may cause side effects, although not everybody experiences them. Possible adverse reactions include:

• Hypersensitivity reactions (symptoms may include swelling, urticaria, and inflammatory redness)
• Ovarian hyperstimulation syndrome (OHSS), which may present as moderate to severe abdominal pain, abdominal distension and firmness, nausea, and vomiting
• Injection site reactions (pain, burning, redness, swelling, etc.)
• Increased liver enzyme levels
• Headache
• Nausea

Consult your physician or pharmacist regarding the use of cetrorelix acetate concomitantly with other medications or supplements.

Cetronax^® is currently available in packs of four. Each pack contains four vials of cetrorelix acetate and four ampoules of sterile water for injection.

• Keep out of sight and reach of children.
• Store at 2–8°C, protected from light and moisture.
• Do not freeze the product.
• The medicine may be used until the expiry date indicated on the packaging. Do not use expired products.
• Keep the product in its original packaging until use.

Cetrorelix: Drug information, UpToDate 2025