Rejun

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Rejun

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Medically reviewed

Rosario Oropesa

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Rejun

Quick Facts

Property Description
Active ingredient Clomifene Citrate
Form Oral Tablet
Pharmacological class Selective Estrogen Receptor Modulator (SERM)
Common purpose Inducing ovulation in women
Origin Synthetic, Non-steroidal compound

What Type of Medicine is Rejun (Clomifene Citrate)?

Rejun is a trade name for a medicine containing the active ingredient Clomifene Citrate, also widely known as Clomiphene Citrate. This compound is classified as an ovulation inducer and formally belongs to the Selective Estrogen Receptor Modulator (SERM) pharmacological class. As a synthetic, non-steroidal oral agent, it is delivered in the form of a single-ingredient tablet for oral administration. This medication is typically issued via prescription and is clinically recognized for its targeted action within reproductive endocrinology.


Composition and General Therapeutic Purpose

The active substance, Clomifene Citrate, is chemically notable for being a racemic mixture composed of two distinct geometric isomers: enclomiphene and zuclomiphene. The general therapeutic purpose of Rejun is to induce ovulation in women who experience ovulatory dysfunction. It achieves this by stimulating the pituitary gland to increase the release of key reproductive hormones, specifically the Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH). This process of initiating hormonal signals serves the purpose of restoring the ovulatory cycle necessary for conception, making Rejun a recognized option for addressing specific fertility challenges related to the absence of regular egg release.

What side effects are possible with Rejun?

Possible Side Effects and Safety Information

The safety profile of Clomifene Citrate (Rejun) is officially documented by regulatory authorities, classifying adverse reactions by frequency and the body system affected. The most frequently observed events in clinical trials are categorized as common.

Officially Documented Adverse Reactions

The most common adverse reactions, based on regulatory trial data, primarily involve the reproductive, vascular, and gastrointestinal systems:

  • Reproductive System: Ovarian enlargement and discomfort, and abnormal uterine bleeding.
  • Vascular System: Vasomotor flushes (hot flashes).
  • Gastrointestinal System: Abdominal-pelvic discomfort, nausea, and vomiting.
  • Other Common Effects: Headache and various visual symptoms.

Serious Safety Considerations

The official safety information highlights certain risks documented in postmarketing reports. The most serious of these include the potential for Ovarian Hyperstimulation Syndrome (OHSS) and the occurrence of thromboembolic events, such as pulmonary embolism. Additionally, postmarketing surveillance includes reports of severe, sometimes irreversible, visual disturbances, including optic neuropathy and retinal occlusion.

Safety Restrictions and Risk Patterns

The regulatory label specifies several conditions under which the medication should not be administered. Contraindications include known pregnancy, the presence of liver disease or a history of liver dysfunction, and undiagnosed abnormal uterine bleeding. Furthermore, the label notes that epidemiological data suggest a potential association between prolonged administration and an increased risk of ovarian neoplasm. The treatment also carries a recognized potential for multiple births.

Overdose and Emergency Response

Overdose and When to Seek Help: Official Regulatory Information for Rejun

Official government regulatory documents define the overdose profile of Rejun (Clomifene Citrate) by listing specific clinical manifestations and mandating clear emergency actions.

Domain Official Regulatory Statement
Documented Manifestations Symptoms may include nausea, vomiting, abdominal pain, and vasomotor flushes. Ocular effects can involve blurred vision, scotoma, and visual flashes. Ovarian enlargement has also been documented.
Emergency Actions Required Seek immediate medical attention for any suspected overdose. Contact a Poison Control Helpline for consultation.
Classification Official Regulatory Statement
Life-Threatening Symptoms Immediate emergency services (e.g., 911) must be contacted if the individual has a seizure, trouble breathing, collapses, or cannot be awakened.
Antidote Status No specific antidote is known for the overdose of Clomifene Citrate.

Resulting Overdose Structure

Official overdose statements:

  • Overdose management is directed at providing symptomatic and supportive treatment.
  • Procedures such as gastric lavage are referenced in the context of supportive measures.
  • No specific dose levels or population-specific considerations regarding altered severity are explicitly defined in the official overdose sections.

Connection to the overall overdose profile: Regulatory information explicitly states the conditions for seeking urgent medical help, triggered by severe outcomes like seizure or collapse. Because there is no known antidote, the official profile emphasizes supportive care for documented clinical effects, such as gastrointestinal upset and visual disturbances.

Therapeutic Uses of Rejun

What Rejun Treats: Main Uses and Benefits

Rejun is commonly used across conditions presenting with acute episodes of reproductive challenge, and it is commonly used to provide supportive assistance for fertility concerns. The medication is relevant in situations where patients experience challenges related to an absence of or irregular ovulation, and it is applied in addressing symptoms that interfere with daily functioning related to fertility.

The medication is generally used to help with female subfertility due to ovulatory disorders, conditions associated with systemic imbalance that affects regular cycles, and certain male fertility challenges. It is applied across domains where additional symptomatic support is needed to address symptom clusters that may become intense or disruptive to symptoms associated with acute or episodic changes.

“This medication is a relevant option when supportive symptom management is appropriate to assist with the complexities of ovulation irregularity.”

This supportive use contributes to improved comfort during periods of heightened symptoms and assists with maintaining a sense of stability when symptoms are more noticeable. It helps patients cope more steadily with symptom fluctuations and supports the patient during difficult episodes.

Quick Fact: Relevant for Symptomatic Irregularity

Regulatory References

  1. NIH MedlinePlus Drug Information

Eligibility and Restrictions for Use

Who Can and Cannot Use Rejun?

Rejun (Clomifene Citrate) is an ovulation-inducing medicine officially approved for adult women who meet specific health and physiological criteria. Use is not applicable to pediatric or older adult populations as the indication is limited to women of childbearing age.


Absolute Contraindications

The medicine must not be used by patients under the following conditions, as formally defined by regulatory labeling:

  • Pregnancy: The medicine is strictly contraindicated, and pregnancy must be excluded before each course of treatment.
  • Liver Disease: Patients with active liver disease or a documented history of liver dysfunction.
  • Ovarian Cysts: Cysts or ovarian enlargement not due to Polycystic Ovary Syndrome (PCOS).
  • Abnormal Bleeding: Uterine bleeding of undetermined origin.
  • Endocrine Dysfunction: Uncontrolled thyroid or adrenal gland disorders, or the presence of an organic intracranial lesion (e.g., pituitary tumor).
  • Hypersensitivity: Known allergy to Clomifene Citrate or any of its components.

Conditional and Limited Use

Official labeling requires caution or conditional use for certain groups:

  • Patients with uterine fibroids or a history of endometriosis must be monitored closely, as use may exacerbate these conditions.
  • Long-term cyclic therapy beyond a total of six cycles is not recommended due to the lack of conclusive data demonstrating safety and efficacy for extended periods.
  • Treatment must be discontinued immediately if the patient develops visual symptoms.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Official regulatory information for Rejun (Clomifene Citrate) establishes a narrow, specific interaction profile, primarily characterized by pharmacodynamic constraints and contraindications related to its metabolic clearance context. The regulatory text for this medicine generally states that interactions with common medicinal products, foods, alcohol, or supplements have not been described or are not known to mandate restrictions.

Documented Interaction Patterns

The most significant interaction is the formal contraindication against co-administration with Ospemifene, another medicine in the Selective Estrogen Receptor Modulator (SERM) class. This restriction is documented due to the risk of pharmacodynamic synergism.

Additionally, a pharmacodynamic interaction is documented with Gonadotropins. Concurrent use may potentiate the follicular response, increasing the officially noted risk of Ovarian Hyperstimulation Syndrome (OHSS).

Interaction-Related Restrictions and Considerations

Classification Constraint / Restriction
Contraindicated Combinations Co-administration with Ospemifene is prohibited.
Metabolic Interactions No specific CYP-mediated or transporter-based interactions are widely documented to require mandatory dosing adjustment.
Population-Specific The medicine is formally contraindicated in patients with liver disease or a history of liver dysfunction, a restriction linked to the medicine's hepatic clearance.

These restrictions define the interaction structure by prohibiting specific SERM combinations and restricting use in populations whose clearance mechanisms are impaired.

Mechanism of Action

Central Receptor Antagonism and Pathway Reset

Clomifene Citrate acts as an antagonist at Estrogen Receptors (ER) located in the hypothalamus and anterior pituitary gland. By blocking the binding of natural estrogen at these central sites, the drug effectively neutralizes the inhibitory negative feedback loop that normally suppresses hormone release, which disrupts the established hormonal regulatory sequence.

Gonadotropin Cascade and Follicular Signaling

The immediate consequence of this central signal block is the systemic increase in the secretion of Gonadotropin-Releasing Hormone (GnRH), which stimulates the pituitary to release elevated levels of FSH and LH. This resulting surge of gonadotropins is the direct physiological mechanism that drives the growth and maturation of ovarian follicles, culminating in the hormonal signal (LH surge) that precedes follicle rupture.

Mechanistic Constraints from Dual Isomer Activity

The drug is a racemic mixture, meaning its necessary anti-estrogenic action centrally extends to peripheral tissues, constituting a mechanistic limitation. This peripheral activity can modulate processes in the cervix and endometrium, occasionally leading to physiological changes (e.g., reduced cervical mucus quality) that partially constrain the overall impact of the central mechanism.

Dosage and Administration Information

Administration Overview

Rejun is typically administered as an oral tablet. The medication should be taken consistently to maintain stable levels within the bloodstream. It is common for the tablets to be swallowed whole with a glass of water.

Timing and Routine

Establishing a regular schedule helps in managing the treatment effectively. While the medication can often be taken with or without food, maintaining a routine—such as taking it at the same time each day—is a standard practice. If a dose is missed, the usual approach is to continue with the next scheduled dose rather than attempting to compensate for the missed one.

Duration of Use

The length of treatment with Rejun is determined by the specific condition being addressed and the individual's response to the medication. Healthcare providers monitor progress over time to evaluate the continued necessity of the treatment. Changes to the regimen are generally managed under professional supervision to ensure the transition is handled appropriately.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Rejun (Clomifene Citrate)


Evidence for Anovulatory Dysfunction and Infertility

Research evidence for Rejun was studied for women who experience irregular or absent ovulation, such as Polycystic Ovary Syndrome (PCOS). The research primarily relies on high-quality Randomized Controlled Trials (RCTs) and comprehensive Systematic Reviews. Research primarily examined outcomes related to whether ovulation occurred, the subsequent Clinical Pregnancy Rate, and the ultimate goal of the Live Birth Rate (LBR).

Across the published scientific literature, studies consistently describe patterns related to ovulation measurements in women with this type of hormonal imbalance. These findings contribute to the broader evidence landscape by documenting the measurements and observations made within the specified patient group. Some meta-analyses describe the overall consistency of the research regarding measurements related to ovulation.

However, research highlights changes measured during the study period that also show a notable difference between the rate of ovulation measured and the final rate of Live Birth. This suggests that the relationship between the measured ovulation and live birth outcomes is not fully established. Long-term data on outcomes extending beyond 12 cycles of exposure are generally limited in the peer-reviewed literature.


Evidence for Women with Unexplained Subfertility

Rejun was evaluated in studies involving women who ovulate regularly but have not conceived, a condition known as unexplained subfertility. Researchers examined outcomes directly related to the final goal: the Live Birth Rate (LBR).

In this specific population, findings were mixed across various randomized trials and meta-analyses. Some pooled data data show patterns related to measured differences when Rejun was used in combination with procedures like Intrauterine Insemination (IUI), but other large-scale reviews indicate that research has not established a clear difference compared to expectant management (no treatment) when focused solely on the LBR. Sample sizes were modest in many of the trials.


Research Examining Hormonal and Semen Parameters in Male Subfertility

The use of Rejun in male fertility challenges was studied in research exploring hormonal factors affecting sperm production. Research in this area is mostly derived from Systematic Reviews, smaller Randomized Studies, and Observational Settings.

Studies monitored outcomes such as changes measured in certain hormone levels (e.g., Testosterone) and in sperm concentration. The evidence highlights what is known — and what is still uncertain regarding the ultimate outcome of a live birth. Follow-up durations were limited in most of these studies, and the evidence is limited as there is a general lack of large, high-quality RCTs that directly track the final outcome of Live Birth Rate.

Key Studies & References

  1. Treatment for anovulation in polycystic ovary syndrome (Guideline)

Frequently Asked Questions (FAQ)

Common questions about Rejun (FAQ)


Q: Is Rejun a type of hormone replacement therapy or an ovulation stimulant?

According to official product information, Rejun (Clomiphene Citrate) is an ovulatory stimulant. It is indicated for treating ovulatory dysfunction in women who wish to become pregnant. Its mechanism involves initiating a hormonal cascade that helps stimulate the ovaries to release an egg.


Q: Can Rejun cause temporary vision problems, and are these a sign of a serious issue?

Visual symptoms such as blurred vision, spots, or flashes may occasionally occur while taking Rejun. The official label warns that these symptoms may make tasks like driving or operating machinery hazardous. Official labeling advises patients to seek guidance from their healthcare provider immediately if visual disturbances occur.


Q: What kind of monitoring (e.g., blood tests, ultrasound) is typically needed while taking Rejun?

Official administration guidelines require a pelvic examination before the first course and before each subsequent course of treatment. Additionally, a diagnosis of pregnancy must be excluded before starting a new cycle. Treatment should not be initiated if the ovaries are abnormally enlarged, and follow-up examinations are used to monitor their size.


Q: Is Rejun considered unsafe for women who have fibroids in the uterus?

Official labeling advises that caution should be exercised when Rejun is used in patients with uterine fibroids. This is due to the potential for the medication to cause the fibroids to enlarge further.


Q: Is Rejun used for infertility caused by factors other than ovulation problems?

Rejun is indicated specifically for the treatment of infertility related to ovulatory dysfunction. The drug label states that other potential causes of infertility should be excluded or adequately treated prior to initiating therapy with Rejun.


Q: Is there a risk of developing ovarian cysts while using Rejun?

Ovarian cysts or ovarian enlargement have been noted in postmarketing reports. The drug label specifically warns against using the medication if a patient has ovarian enlargement or cysts that are not due to polycystic ovary syndrome (PCOS).


Q: How long after finishing a cycle of Rejun does ovulation typically occur?

Information from regulatory references indicates that ovulation usually occurs approximately 5 to 10 days after a patient completes a 5-day course of Rejun therapy.


Q: Is Rejun an FDA-approved treatment for female infertility in general?

Rejun is indicated for the treatment of ovulatory dysfunction in women desiring pregnancy. Its approval is specific to this condition, which is a factor in female subfertility.


Q: Are there different strengths or formulations of Rejun available (e.g., 25mg, 50mg, 100mg)?

Official administration guidelines indicate that a range of daily doses are used, starting at the lowest effective dose. The prescribing information confirms the existence of higher and lower dosages that may be considered by a healthcare professional.


Q: How soon can a person typically expect to see a result, such as a menstrual period or ovulation, after starting Rejun?

Ovulation usually occurs between 5 and 10 days after a patient has completed the 5-day course of Rejun therapy. A menstrual period will follow if conception does not occur.


Q: Is Rejun known by any other brand names containing the same active ingredient?

Yes, Rejun contains the active ingredient Clomiphene Citrate. This compound is also widely known and sold under the brand names Clomid and Serophene.


Q: What should be done if a dose of Rejun is forgotten?

Information regarding a forgotten dose advises against taking two doses at once to make up for a missed dose. Patients are advised to consult their prescribing clinician for guidance on what action to take.


Q: Is it common to experience abnormal bleeding or spotting in between periods while taking Rejun?

Official safety information lists breakthrough bleeding or spotting, sometimes classified as intermenstrual spotting, as a common adverse event. This side effect is noted to occur in more than 1% of patients in clinical trial data.


Q: Is Rejun known to cause weight gain that lasts after the treatment is stopped?

Weight gain is noted as a possible side effect in drug reports, although the frequency of this occurrence in clinical trials is not widely reported. Regulatory sources do not contain information regarding whether the weight gain persists after the treatment is concluded.


Q: What are the potential signs of an allergic reaction to Rejun?

Hypersensitivity to the medicine is listed as a contraindication. Postmarketing surveillance reports include symptoms like acne, rash, erythema, and urticaria, which can be associated with allergic or hypersensitivity reactions. Patients are advised to contact emergency services or their healthcare provider immediately if they experience signs of a severe allergic reaction.


Q: Should Rejun be taken at a specific time of day?

The medication is taken once a day for the full 5-day treatment course. Official administration instructions do not specify a mandatory time of day (e.g., morning or evening) for taking the tablet.


Q: What should I do if I experience headaches that are more severe than usual while on Rejun?

Headache is listed as a common side effect of Rejun, and severe headaches, including migraines, have been reported. Information on severe symptoms advises patients to discontinue the medication and seek guidance from their healthcare provider immediately.


Q: Is a follow-up consultation required if I do not ovulate during my first cycle of Rejun?

The administration guidelines indicate that if no ovulation occurs after the initial course, a healthcare provider may determine that a subsequent course of treatment is appropriate. Similarly, if ovulation occurs but pregnancy is not achieved after a certain number of ovulatory responses, further treatment is generally not recommended.


Q: What is the half-life of Rejun in the body?

According to pharmacokinetic data, the half-life of Clomiphene in the body is approximately 5 to 7 days. This relates to the time it takes for half of the drug to be eliminated from the system.


Q: Is it normal to feel dizzy or lightheaded while taking Rejun?

Dizziness or lightheadedness is listed as a possible side effect of Rejun, although the frequency in clinical trials is not explicitly reported. Official patient safety information notes that this side effect may cause some people to feel dizzy or lightheaded while using the medication.

How should Rejun be stored and disposed of?

Official Storage and Disposal Requirements

Rejun (Clomiphene Citrate) tablets must be stored according to regulatory specifications to ensure stability and safety. The drug requires controlled room temperature, generally maintained between 15 C and 30 C (59 F and 86 F). The container must be kept tightly closed in a cool, dry place and protected from excessive heat, light, and moisture.

For safety, the medication must be stored out of the reach of children.

To dispose of unused or expired tablets, the official guidance recommends a drug take-back program. Since the tablets are not on the FDA flush list, if a take-back option is unavailable, they should be mixed with an undesirable substance (e.g., dirt, used coffee grounds), sealed in a container, and discarded in the household trash. The product should not be allowed to enter water systems.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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