Peptide education
Cetrorelix
Cetrorelix acetate · Cetrotide
Cetrorelix is a prescription medicine used during ovarian stimulation to help prevent an early luteinizing hormone (LH) surge. The U.S. product Cetrotide is given under the skin as part of fertility treatment, with the timing and ovarian response monitored by a clinician.
An established fertility medicine for preventing a premature LH surge, used within a monitored ovarian stimulation cycle.
Overview
Quick answer
Cetrorelix holds back a hormone signal that could trigger ovulation too soon. It is not the gonadotropin medicine used to grow follicles and it does not guarantee pregnancy. Older studies of a 3 mg dose are different from the 0.25 mg daily schedule in the U.S. Cetrotide label.
Why is cetrorelix used in fertility treatment?
It helps prevent an early LH surge while follicles are developing. That gives the care team more control over the timing of final egg maturation and retrieval.
What does the U.S. label say about dosing?
The Cetrotide label describes 0.25 mg under the skin once daily, beginning on stimulation day 5 in the morning or evening, or day 6 in the morning, and continuing through the day hCG is given. The fertility team determines the treatment plan. This is label context, not an individual prescription.
Is a 3 mg dose the same schedule?
No. A randomized study used an initial 3 mg dose, with additional doses in some patients. That research regimen should not be substituted for the current labeled daily schedule.
What safety issues matter?
Allergic reactions, including serious reactions, have been reported. Ovarian hyperstimulation syndrome can occur during the wider stimulation cycle. The label also lists pregnancy, lactation, severe kidney impairment, and certain allergies as reasons not to use Cetrotide.
Evidence
Evidence snapshot
The U.S. label identifies inhibition of premature LH surges during controlled ovarian stimulation and summarizes human studies of daily and single-dose regimens.
The two phase 3 multiple-dose groups had reported post-treatment LH and progesterone surge rates of 1.9% and 1.0%. Definitions and study populations matter.
A successful block of an LH surge does not remove the risk of ovarian hyperstimulation or allergic reactions during treatment.
Claims
Common claims vs evidence
| Claim | Human evidence | Mechanistic evidence | Verdict |
|---|---|---|---|
| Cetrorelix helps prevent ovulation from happening too early during stimulation. | The Cetrotide label describes clinical studies measuring premature LH surges during controlled ovarian stimulation. Some surges still occurred in the daily-dose groups. | Cetrorelix blocks pituitary GnRH receptors, reducing LH release and delaying the surge that can lead to ovulation. | Supported for the labeled, monitored setting. A suppressed LH surge is not a guarantee of retrieval, pregnancy, or live birth. |
| A single 3 mg dose proves the daily 0.25 mg product can be replaced. | An older randomized trial studied 3 mg in 115 patients, and some needed additional doses. The label describes a 0.25 mg daily regimen for the currently referenced Cetrotide kit. | The regimens are distinct. Study results do not authorize switching a patient's treatment. | |
| Cetrorelix removes the risk of ovarian hyperstimulation syndrome. | The Cetrotide label reports ovarian hyperstimulation syndrome among events seen during treatment. Monitoring and decisions about the rest of the stimulation cycle still matter. | Not supported. A GnRH antagonist does not make a stimulation cycle risk-free. |
Bottom line
Main takeaway
Cetrorelix helps the fertility team manage timing. It does not mature eggs on its own.
Check the exact medicine and instructions with the fertility team, including the start day, monitoring plan, allergy history, and what to do if symptoms develop.
Separate the label's daily-dose phase 3 results from the older single-dose studies and their specific definitions of a premature LH surge.
Identity
What it is
Cetrorelix is a synthetic peptide with ten amino acids. Cetrotide contains cetrorelix acetate in a powder-and-diluent kit for injection beneath the skin.
In controlled ovarian stimulation, gonadotropins are used to support follicle development. Cetrorelix has a different job: it suppresses the signal that can cause premature ovulation.
Use context
Routes, doses, and cycle patterns
The following regimens describe a U.S. product label and published studies. They are not recommendations for starting, changing, or replacing an individual fertility plan.
Human studies and product labels
Cetrotide U.S. label
- Purpose
- Inhibit premature LH surges during controlled ovarian stimulation
- Context
- Prescription product label
- Route
- Subcutaneous
- Amount
- 0.25 mg
- Frequency
- Once daily, beginning on stimulation day 5 in the morning or evening, or day 6 in the morning
- Duration
- Continued daily until the day hCG is administered
The label places treatment within clinician-directed ovarian stimulation and ultrasound assessment. This is not a personalized schedule.
Single-dose cetrorelix trial
- Purpose
- Prevent a premature LH surge during IVF stimulation
- Context
- Randomized study compared with depot triptorelin
- Route
- Subcutaneous
- Amount
- Initial 3 mg dose, with 0.25 mg additional doses for some participants
- Frequency
- Initial single dose, with additional doses when required by the study
- Duration
- Depended on the timing of hCG
This is a study-reported regimen, not a replacement for the current 0.25 mg label.
What varies
- Treatment timing: the clinician coordinates the antagonist, stimulation medicines, monitoring, and any trigger.
- Product: a powder-and-diluent kit and a prefilled injection are not automatically interchangeable.
- Medical history: pregnancy, lactation, severe renal impairment, and specified allergies affect use of Cetrotide.
Research
Research evidence
The label summarizes phase 3 studies of daily cetrorelix during controlled ovarian stimulation. A separate randomized study examined a 3 mg initial dose against a long triptorelin protocol. Those findings describe specific populations and protocols, not a guarantee of pregnancy or a general fertility benefit.
| Study / evidence area | Population | Design | Product context | Main outcome | Limitations | Weight |
|---|---|---|---|---|---|---|
| Cetrotide multiple-dose phase 3 studies | Women undergoing controlled ovarian stimulation for assisted reproduction | One active-comparator and one non-comparative study, summarized in the label | 0.25 mg cetrorelix daily | After treatment began, the label's combined LH and progesterone surge endpoint occurred in 1.9% and 1.0% of the two daily-dose groups. | The studies had different designs and excluded some populations. Surge prevention is not the same outcome as live birth. | Substantial human evidence |
| Single-dose cetrorelix versus triptorelin | Patients undergoing ovarian stimulation for IVF and embryo transfer | Multicenter randomized trial, 115 cetrorelix and 39 triptorelin patients | Initial 3 mg cetrorelix versus depot triptorelin | No LH surge was reported after cetrorelix was given. The cetrorelix group had fewer oocytes and embryos. | Some cetrorelix patients received additional doses. This older regimen is different from the daily 0.25 mg schedule in the referenced label. | Controlled human study |
| Cetrorelix versus ganirelix | 185 patients undergoing programmed ovarian stimulation for assisted reproduction | Open-label randomized comparison | Initial 3 mg cetrorelix versus daily 0.25 mg ganirelix | The study reported no premature LH surge in either group by its day-of-trigger definition. | It did not compare the two current daily U.S. product regimens and cannot establish patient-level interchangeability. | Controlled human study |
Cautions
Safety and unknowns
- Injection-site redness, itching, swelling, and bruising were reported. Nausea and headache also appeared in the label's clinical safety data.
- Hypersensitivity reactions, including serious reactions, have been reported, including with the first dose. Tell the fertility team about known allergies or prior reactions.
- The Cetrotide label contraindicates use in known or suspected pregnancy, during lactation, with severe renal impairment, and with specified hypersensitivities to the drug, mannitol, GnRH, related analogs, or extrinsic peptide hormones.
- Ovarian hyperstimulation syndrome can occur during fertility treatment. Contact the fertility clinic promptly for abdominal pain or bloating, vomiting, or faintness. Difficulty breathing or chest pain needs emergency care.
Product quality
Product identity and quality
The referenced Cetrotide product has a labeled vial and supplied diluent. The label's evidence does not verify another product's contents, sterility, or storage history.
Product and strength
The labeled Cetrotide kit contains 0.25 mg cetrorelix. A study dose or a different product should not be assumed to have the same preparation or instructions.
Handling and storage
The label specifies refrigeration and protection from light for this product. Follow the product's own instructions and the fertility team's guidance.
Mechanism
How it is proposed to work
Cetrorelix blocks a pituitary receptor for GnRH. This reduces LH release and helps delay the surge that would otherwise trigger ovulation.
GnRH ordinarily signals the pituitary to release LH and FSH. Cetrorelix competes for the receptor, with a more pronounced effect on LH at the doses described in the label.
The label describes reversible effects after treatment stops and no detected initial gonadotropin release consistent with an antagonist mechanism.
FAQ
Common questions
What is cetrorelix used for?
Cetrotide is labeled to inhibit premature LH surges during controlled ovarian stimulation. It is part of a monitored fertility treatment, not a drug that grows follicles by itself.
Is the 3 mg study regimen the current Cetrotide schedule?
No. An older trial studied an initial 3 mg dose, sometimes followed by additional doses. The current U.S. Cetrotide label describes 0.25 mg once daily.
Does cetrorelix eliminate ovarian hyperstimulation syndrome?
No. Ovarian hyperstimulation syndrome can occur during a stimulation cycle. Symptoms and ovarian response need assessment by the fertility team.
Details
Technical details
Sources
References
- 1.
DailyMed. Cetrotide (cetrorelix acetate for injection) prescribing information
U.S. product label for indication, administration, trial results, contraindications, and safety.
- 2.
PubMed. Prospective randomized study of single-dose cetrorelix versus depot triptorelin in IVF
doi:10.1016/s0015-0282(99)00524-5 PMID:10685535
Randomized comparison of a 3 mg cetrorelix regimen with a long triptorelin protocol.
- 3.
PubMed. Randomized trial comparing cetrorelix and ganirelix in assisted reproduction
doi:10.1016/j.fertnstert.2005.03.016 PMID:16009165
Open-label trial comparing a 3 mg cetrorelix regimen with daily 0.25 mg ganirelix.
- 4.
NHS. IVF: possible complications
Patient-facing information on symptoms and urgent care during fertility treatment.