What Does Ciscure Do? An Overview of Its Role in Fertility Treatment

October 7, 2025 •

4 min read

Over 8 million infants have been born worldwide through assisted reproductive technology (ART) since 1978. In this complex process, one medication that plays a crucial role is Ciscure, which is used to prevent premature ovulation during controlled ovarian stimulation.

Quick Summary

Ciscure is an injectable medication containing cetrorelix, a GnRH antagonist, used during assisted reproductive techniques like IVF. It works by blocking the natural hormone cascade that triggers early ovulation, allowing for optimal egg maturation and improving the chances of a successful egg retrieval and fertilization.

Key Points

Inhibits Premature Ovulation: Ciscure's primary function is to prevent an untimely LH surge, which can cause eggs to be released too early during fertility treatments like IVF.
Contains Cetrorelix: The active ingredient, cetrorelix, is a GnRH antagonist that blocks receptors in the pituitary gland.
Crucial for IVF: By controlling ovulation, Ciscure ensures that eggs reach optimal maturity before they are collected during the retrieval procedure.
Administered by Injection: Ciscure is typically administered as a subcutaneous injection, often into the abdomen, following a schedule determined by a doctor.
Potential Side Effects: Common side effects include irritation at the injection site, headache, and nausea, while a more serious risk is Ovarian Hyperstimulation Syndrome (OHSS).
Not for Pregnancy/Breastfeeding: Ciscure is contraindicated in women who are pregnant or breastfeeding, as it can cause harm to a fetus or newborn.
Requires Medical Supervision: The use of Ciscure and the entire IVF protocol must be managed by a qualified healthcare professional.

Understanding the Hormonal Control of Ovulation

Before delving into what does Ciscure do, it is essential to understand the natural hormonal process of ovulation. In a typical menstrual cycle, the hypothalamus releases Gonadotropin-Releasing Hormone (GnRH), which prompts the pituitary gland to produce Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH). FSH stimulates the growth of follicles in the ovaries, and once a follicle matures, a sudden surge of LH triggers the release of the egg, or ovulation.

During assisted reproductive techniques like in-vitro fertilization (IVF), a woman is given medications to stimulate the ovaries to produce multiple mature eggs. An uncontrolled, premature surge of LH could cause the release of these eggs before they reach optimal maturity, compromising the treatment's success. Ciscure is prescribed precisely to prevent this. It is a pharmaceutical product manufactured by Emcure Pharmaceuticals Ltd..

How Ciscure Works: The Mechanism of Cetrorelix

Ciscure's active ingredient is cetrorelix, which belongs to a class of drugs known as GnRH antagonists. Its mechanism is based on disrupting the hormonal chain of command at a critical point:

Cetrorelix, the active component of Ciscure, binds to the GnRH receptors in the pituitary gland.
By binding to these receptors, it effectively blocks the action of natural GnRH.
This blockade inhibits the pituitary gland from releasing LH and FSH.
The most significant effect is the suppression of the premature LH surge, preventing premature ovulation.

By controlling the LH surge, Ciscure gives fertility specialists precise control over the timing of egg maturation and retrieval. This ensures that the eggs are collected at the optimal stage of development, which is crucial for a successful IVF cycle.

Ciscure's Role in In-Vitro Fertilization (IVF)

In an IVF cycle, Ciscure is typically used for a specific duration of the controlled ovarian stimulation phase. This process involves:

Ovarian Stimulation: Hormonal injections of FSH are administered to stimulate the growth of multiple follicles in the ovaries.
Monitoring: The growth and number of follicles are closely monitored using ultrasound.
Ciscure Administration: Once the follicles reach a certain size, Ciscure injections are started to prevent the spontaneous LH surge. The injection is administered subcutaneously into the abdomen, and patients are advised to use a different site each day to minimize irritation.
Trigger Shot: When the follicles have reached the optimal size, an injection of human chorionic gonadotropin (hCG) is given to trigger final egg maturation.
Egg Retrieval: The eggs are retrieved approximately 34 to 36 hours after the hCG injection, before the natural ovulation would have occurred.

Potential Side Effects and Precautions

Like all medications, Ciscure can cause side effects. It is important for patients to be aware of these and to report any concerns to their healthcare provider.

Common Side Effects

Injection site reactions, including pain, redness, itching, or swelling
Headache
Nausea
Abdominal pain

Serious Side Effects

Ovarian Hyperstimulation Syndrome (OHSS): This can occur as a result of the overall ovarian stimulation, and symptoms include severe abdominal pain, bloating, nausea, vomiting, diarrhea, and sudden weight gain. A doctor should be consulted immediately if these symptoms appear.
Allergic Reactions: Severe reactions such as swelling of the face, lips, tongue, or throat, hives, or difficulty breathing, though rare, should be treated as a medical emergency.

Ciscure vs. GnRH Agonists

Infertility treatment protocols have evolved, offering different approaches to suppress the LH surge. GnRH antagonists like Ciscure are often compared with GnRH agonists, such as leuprolide (Lupron), which work differently to achieve a similar goal. The choice of medication depends on the specific treatment protocol and patient characteristics.


Feature	Ciscure (GnRH Antagonist)	GnRH Agonist (e.g., Lupron)
Mechanism	Blocks GnRH receptors to immediately inhibit LH and FSH release.	Causes an initial surge of GnRH, followed by downregulation and suppression of LH and FSH.
Onset of Action	Rapid onset of suppression, typically within hours.	Initial flare-up effect, with suppression taking a week or more to achieve.
Length of Treatment	Short-term usage, typically starting later in the cycle and lasting only a few days.	Longer-term usage, often started in the cycle preceding ovarian stimulation.
Risk of OHSS	Associated with a lower risk of severe OHSS, as an antagonist protocol can allow for a safer trigger shot.	Can be associated with a higher risk of OHSS in certain patients.

Conclusion

Ciscure, containing the active ingredient cetrorelix, plays a pivotal role in modern assisted reproductive technologies. By acting as a GnRH antagonist, it gives fertility specialists the control they need to prevent premature ovulation during IVF and other procedures. This precision ensures that eggs can be retrieved at their optimal maturity, significantly improving the chances of a successful outcome. While generally well-tolerated, it is vital for patients to follow their doctor's instructions closely and be aware of potential side effects, particularly the signs of OHSS.

Frequently Asked Questions

Ciscure is used to prevent premature ovulation in women undergoing controlled ovarian stimulation as part of assisted reproductive technologies (ART) such as in-vitro fertilization (IVF).

The active ingredient in Ciscure, cetrorelix, is a GnRH antagonist. It works by blocking the GnRH receptors in the pituitary gland, which suppresses the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) and, consequently, prevents a premature LH surge.

The primary benefit of Ciscure is that it gives doctors precise control over the timing of egg maturation. This ensures that the eggs are retrieved at the optimal time during an IVF cycle, increasing the chances of successful fertilization and conception.

Ciscure is administered via subcutaneous injection. A healthcare professional may instruct you on how to administer it at home, typically into the lower abdomen.

Common side effects include injection site reactions (redness, itching, swelling), headache, and nausea. These are typically mild and often resolve on their own.

OHSS is a condition where the ovaries become swollen and painful, and it is a risk with any controlled ovarian stimulation. While Ciscure may be associated with a lower risk compared to some other medications, patients should be vigilant for symptoms like severe abdominal pain, bloating, nausea, and vomiting, and contact their doctor immediately if they occur.

Ciscure is contraindicated in women who are pregnant or breastfeeding, those with a known hypersensitivity to cetrorelix or other GnRH analogs, and individuals with severe kidney disease.

Ciscure is not used during pregnancy. Studies have shown that its effects are reversible in the menstrual cycle following treatment. It does not appear to affect subsequent pregnancies that occur naturally.

Ciscure is a brand name for the drug cetrorelix. Cetrotide is another brand name for the same active ingredient, and a generic version of cetrorelix acetate has been approved by the FDA.