CETRORELIX ACETATE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CETRORELIX ACETATE (CETRORELIX ACETATE).
Gonadotropin-releasing hormone (GnRH) antagonist. Competitively blocks GnRH receptors on pituitary gonadotropes, inhibiting secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
| Metabolism | Metabolized via peptidolysis; not significantly metabolized by cytochrome P450 enzymes. |
| Excretion | Primarily renal (excreted unchanged in urine ~42% within 24 hours; total urinary recovery ~66-69% over 8 days); biliary/fecal elimination accounts for <5%. |
| Half-life | Terminal elimination half-life: ~7-9 hours in healthy adults; prolonged to ~14-30 hours in patients with hepatic or renal impairment (clinical significance: no dose adjustment needed for mild-to-moderate renal or hepatic impairment, but caution in severe cases due to potential accumulation). |
| Protein binding | 86-96% bound to albumin (alpha-1-acid glycoprotein binding not significant). |
| Volume of Distribution | Apparent Vd: 1.14 L/kg (range 0.8–1.4 L/kg), indicating distribution primarily into extracellular fluid; not extensively tissue-bound. |
| Bioavailability | Subcutaneous: ~85% (absolute bioavailability). |
| Onset of Action | Subcutaneous: Maximal suppression of LH and FSH occurs within 2-4 hours; clinical suppression of premature ovulation is achieved within 30 minutes to 1 hour post-injection. |
| Duration of Action | Subcutaneous: LH/FSH suppression maintained for ≥4 hours after a single dose (sufficient to prevent LH surge for the required timeframe in controlled ovarian stimulation); repeated daily dosing (0.25 mg) maintains suppression. |
250 mcg subcutaneously once daily, starting on day 7 of ovarian stimulation and continuing until the day of hCG administration. Alternatively, a single 3 mg subcutaneous dose on day 7 of stimulation if hCG is given on day 9.
| Dosage form | POWDER |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment (GFR ≥30 mL/min). Insufficient data for severe impairment (GFR <30 mL/min); use with caution. |
| Liver impairment | No dose adjustment recommended for mild to moderate hepatic impairment (Child-Pugh A or B). Not studied in severe impairment (Child-Pugh C); use with caution. |
| Pediatric use | Not indicated in pediatric patients (safety and efficacy not established). |
| Geriatric use | No specific dose adjustment; limited experience in women >65 years. Use with caution due to reduced renal and hepatic function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CETRORELIX ACETATE (CETRORELIX ACETATE).
| Breastfeeding | Not recommended during breastfeeding. M/P ratio unknown; cetrorelix is likely excreted in milk based on molecular weight; potential for adverse effects in the infant, including hormonal disruption. |
| Teratogenic Risk | Category X. Risk of congenital anomalies if pregnancy occurs. Avoid use during pregnancy; confirm negative pregnancy test before initiation. First trimester: No data; theoretical risk due to hormonal antagonism. Second and third trimesters: Not indicated for use; may interfere with pregnancy maintenance. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to cetrorelix acetate, mannitol, or any component.","Pregnancy and lactation.","Postmenopausal women.","Severe hepatic or renal impairment (safety not established)."]
| Precautions | ["Hypersensitivity reactions including anaphylaxis and urticaria.","Ovarian hyperstimulation syndrome (OHSS) due to gonadotropin therapy.","Pregnancy category X: contraindicated in pregnancy.","May cause fetal harm if administered during pregnancy."] |
| Food/Dietary | No significant food interactions. No dietary restrictions required. |
| Clinical Pearls |
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| Fetal Monitoring |
| Monitor ovarian response via ultrasound and estradiol levels during controlled ovarian stimulation. If unintentional pregnancy occurs, discontinue drug and monitor fetal development via ultrasound. No specific fetal monitoring required for exposure; consider referral to maternal-fetal medicine. |
| Fertility Effects | Used for controlled ovarian stimulation in ART; inhibits premature LH surges, improving oocyte yield. No long-term negative impact on fertility; transient effect only during treatment cycle. Return to normal ovulation after discontinuation. |
| Administer subcutaneously in the lower abdominal wall. Rotate injection sites. Reconstitute with 1 mL of sterile water for injection or provided diluent; use immediately after reconstitution. Monitor for ovarian hyperstimulation syndrome (OHSS), especially in patients with polycystic ovary syndrome. Cetrorelix can cause transient injection site reactions. It is contraindicated in pregnancy and during lactation. |
| Patient Advice | Cetrorelix is used to prevent premature ovulation during fertility treatments. · Inject the medication exactly as prescribed, usually once daily in the abdomen. · Rotate injection sites and do not inject into irritated or bruised skin. · Do not skip doses; if a dose is missed, contact your healthcare provider. · Report any symptoms of OHSS such as severe pelvic pain, nausea, vomiting, or sudden weight gain. · This drug is not for use during pregnancy; inform your doctor if you think you are pregnant. |