CETROTIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CETROTIDE (CETROTIDE).
Cetrorelix is a synthetic decapeptide with gonadotropin-releasing hormone (GnRH) antagonistic activity. It competitively blocks GnRH receptors on the pituitary gland, reducing the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
| Metabolism | Cetrorelix is metabolized via peptidase cleavage and is primarily eliminated unchanged in urine and feces. |
| Excretion | Primarily renal excretion of unchanged drug (approx. 40-50%) and metabolites; remainder excreted in feces via biliary elimination. Total recovery in urine and feces accounts for >90% of dose. |
| Half-life | Terminal elimination half-life is approximately 36 hours after subcutaneous administration. This long half-life supports once-daily dosing for continuous GnRH antagonist effect. |
| Protein binding | Approximately 80% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Approximately 0.7 L/kg, indicating distribution primarily into extracellular fluid and limited tissue binding. |
| Bioavailability | Subcutaneous administration: approximately 85% absolute bioavailability compared to intravenous injection. |
| Onset of Action | Subcutaneous: Suppression of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) occurs within 1-2 hours, with maximal suppression achieved by 4-8 hours. |
| Duration of Action | Single subcutaneous injection suppresses LH and FSH for at least 24 hours, allowing once-daily dosing. Continuous therapy maintains suppression throughout the treatment period. |
0.25 mg subcutaneously once daily starting on day 7 of ovarian stimulation and continuing until the day of hCG administration.
| Dosage form | POWDER |
| Renal impairment | No specific dose adjustment is recommended for patients with renal impairment; however, caution is advised in severe impairment due to limited data. |
| Liver impairment | No specific dose adjustment is recommended for patients with hepatic impairment; however, caution is advised in severe impairment due to limited data. |
| Pediatric use | Not indicated for pediatric use; safety and efficacy have not been established. |
| Geriatric use | Not indicated for geriatric use; safety and efficacy have not been established in women over 65 years. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CETROTIDE (CETROTIDE).
| Breastfeeding | No data on cetrorelix excretion in human milk. M/P ratio unknown. Given its peptide nature and short half-life, excretion is unlikely but not confirmed. Caution advised; avoid use in nursing mothers unless clearly needed. |
| Teratogenic Risk | Pregnancy Category X. Cetrorelix is contraindicated during pregnancy due to risk of fetal harm. In animal studies, it caused embryolethality and teratogenicity at doses lower than human exposure. No adequate human studies exist. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to cetrorelix, GnRH, or any other GnRH analog.","Known or suspected pregnancy.","Breastfeeding.","Severe renal impairment (creatinine clearance <30 mL/min).","Pre-existing moderate to severe hepatic impairment."]
| Precautions | ["Hypersensitivity reactions (e.g., anaphylaxis) have been reported.","Ovarian hyperstimulation syndrome (OHSS) may occur; monitor during stimulation.","Use caution in patients with active allergic conditions or history of asthma."] |
| Food/Dietary | No known food interactions. No dietary restrictions required. |
| Clinical Pearls |
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| Monitor for signs of ovarian hyperstimulation syndrome (OHSS) during controlled ovarian stimulation. If inadvertent pregnancy occurs, discontinue cetrorelix and monitor fetal development via ultrasound. |
| Fertility Effects | Cetrorelix is used therapeutically to prevent premature LH surges in assisted reproduction, thereby regulating fertility. It does not impair long-term fertility; ovarian function returns to baseline after discontinuation. |
| Cetrotide (cetrorelix) is a GnRH antagonist used in controlled ovarian stimulation to prevent premature LH surges. Administer subcutaneously in the lower abdominal wall; rotate sites. Monitor for ovarian hyperstimulation syndrome (OHSS). Onset of action is immediate; does not cause flare effect like GnRH agonists. Dose adjustment not required in renal or hepatic impairment. Use with caution in patients with allergies to GnRH analogs or mannitol. |
| Patient Advice | Inject exactly as prescribed, at the same time each day during the stimulation cycle. · Do not skip doses; missing a dose may increase risk of premature ovulation. · Report any signs of allergic reaction, such as rash, hives, or difficulty breathing. · Mild injection site reactions (redness, swelling, itching) are common and usually resolve. · Avoid pregnancy prior to the procedure; use non-hormonal contraception if needed. · Understand the risk of OHSS: symptoms include severe pelvic pain, nausea, vomiting, sudden weight gain, and decreased urination. |