Мифегин

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Мифегин

Treatment option: Pregnancy, Uterine Leiomyomata

Medically reviewed

Laura Arias

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 Мифегин

Quick Facts

Property Description
Active ingredient Mifepristone
Form Tablet (for oral administration)
Pharmacological class Progesterone Receptor Modulator (Antiprogestin)
Origin Synthetic steroid
General purpose Hormonal antagonism for reproductive and metabolic control

What is Мифегин? Definition and Identity

Мифегин is a specialized medicinal product containing Mifepristone as its sole active ingredient. This compound is classified as a potent synthetic steroid that is exclusively administered orally in the tablet dosage form. Mifepristone's specific chemical structure, represented by the formula C29H35NO2, and its high purity are necessary for its precise receptor-binding function.

Classification: Antiprogestin and Antiglucocorticoid

Мифегин belongs to the pharmacological class known as a Progesterone Receptor Modulator, acting primarily as an antiprogestin. This designation means it works by competitively binding to and blocking the actions of the natural hormone, progesterone. Its efficacy is recognized as pivotal in hormone-dependent applications. Additionally, Mifepristone is also categorized as an Antiglucocorticoid, as it blocks the receptor for the stress hormone cortisol, which is key in its secondary applications. This unique dual-antagonist activity provides a specialized therapeutic approach.

General Purpose and Benefit of Mifepristone

The general therapeutic purpose of Mifepristone is rooted in its ability to disrupt or modify specific hormonal signals. Due to its action as an antiprogestin, its primary utility is to initiate the necessary uterine changes required for the medical termination of intrauterine pregnancy. Mifepristone is categorized as an essential medicine for this purpose, reflecting its recognized role in reproductive healthcare. Furthermore, its antiglucocorticoid activity provides benefit in controlling systemic metabolic issues, such as managing the elevated blood sugar associated with conditions of excessive cortisol activity.

Regulatory References

  1. pharmacological studies
  2. WHO Essential Medicines

What side effects are possible with Мифегин?

Possible Side Effects and Safety Information

This section describes the officially documented adverse reactions and safety characteristics of Mifepristone (Мифегин) as classified in regulatory documents.

Frequency and System-Organ Classes

The adverse reactions are categorized based on their reported frequency and the major physiological systems involved, aligning with regulatory standards. Most Common effects, defined in U.S. regulatory data as occurring in over 15% of patients, include gastrointestinal issues such as nausea, vomiting, and diarrhea, along with systemic effects like weakness, headache, dizziness, and fever or chills [MIFEPREX Label]. The Reproductive System is notably involved, with expected vaginal bleeding or spotting and abdominal/pelvic cramping being nearly universal.

Serious Adverse Reactions and Safety Constraints

Official labeling highlights the risk of Serious Adverse Reactions, which include Prolonged Heavy Vaginal Bleeding that may require intervention and Serious Bacterial Infection (sepsis/septic shock), which is classified as Very Rare [SmPC - HPRA] but may present atypically without fever. Uterine rupture is also documented as a very rare event.

Regulatory safety constraints list conditions where the medicine should not be used, such as confirmed ectopic pregnancy, chronic adrenal failure, and inherited porphyria. The use of Mifepristone is generally not recommended in individuals with severe hepatic or renal impairment due to the absence of specific safety studies in these populations [SmPC - WHO].

Overdose and Emergency Response

Overdose and When to Seek Help

Overdose Information

Official regulatory information emphasizes that death has been associated with drug intoxication/overdose in post-marketing reports for mifepristone. While a specific toxic dose is not defined in patient information, the focus for emergency action is on life-threatening complications that can occur with the therapeutic regimen, such as severe infection (sepsis) and heavy vaginal bleeding (hemorrhage). These events are extremely rare but require urgent attention.

Classification Detail (Regulatory Context)
Severity Implicitly categorized as a serious, potentially life-threatening emergency.
Associated Risk Factors Combined drug intoxication/overdose reported in post-marketing fatalities.

Required Emergency Action

Contact the poison control helpline immediately in case of overdose. Call emergency services (911) right away if the patient has collapsed, had a seizure, has trouble breathing, or cannot be awakened.

When Immediate Medical Help Is Required

Seek immediate medical attention for any signs of severe complications, which include:

  • Fever of 100.4 F (38 C) or higher that lasts more than four hours.
  • Heavy bleeding, such as soaking through two thick, full-size sanitary pads per hour for two consecutive hours.
  • Severe pain or tenderness below the waist.
  • General symptoms of illness, such as weakness, nausea, vomiting, or diarrhea, lasting more than 24 hours after administration, even without fever or pain.

Therapeutic Uses of Мифегин

Mifegyne (mifepristone) is a medication applied across therapeutic domains within reproductive health, commonly used across conditions presenting with acute episodes. The medication is considered relevant for the medical termination of pregnancy, alongside other clinical scenarios such as the induction of labor for fetal death in utero and to prepare the cervix before surgical termination. This application is relevant for easing the functional stress associated with the process.

The medicine helps address symptom clusters that may become intense or disruptive during these periods, providing supportive relief in clinical settings that involve acute or unstable symptom patterns. It is applied in addressing situations where short-term symptomatic assistance is needed. The support provided is commonly used to help with symptomatic assistance. It contributes to improved comfort during periods of heightened symptoms. Quick Fact: Relief for symptoms related to heightened physiological activity. The overall support assists with maintaining functional stability and may assist with maintaining a sense of stability when symptoms are more noticeable, contributes to easing the overall symptom load.

Eligibility and Restrictions for Use

The eligible population for Мифегин (Mifepristone) is strictly defined by regulatory authorities as adult women who meet specific clinical and gestational criteria. Use is permissible only for a confirmed intrauterine pregnancy that does not exceed the maximum gestational age specified in the regulatory label.

Absolute Contraindications (Must Not Use)

The medicine is strictly prohibited for patients with a confirmed or suspected ectopic pregnancy, chronic adrenal failure, or those receiving concurrent long-term corticosteroid therapy. Absolute restrictions also apply to patients with hemorrhagic disorders or those taking anticoagulant medication, due to a heightened risk of bleeding. A known inherited porphyria, an intrauterine device (IUD) in place (unless removed), or a hypersensitivity to mifepristone are also absolute contraindications.

Restricted and Not Recommended Use

Use is generally not recommended in patients with severe hepatic impairment or severe renal impairment due to a lack of specific data on drug metabolism in these populations. The safety and effectiveness are not established in adolescents under 18 years of age. Furthermore, use is not recommended during lactation as the substance passes into breast milk, and its effects on the infant are unknown.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Mifepristone (Мифегин) is subject to official regulatory restrictions concerning co-administration with various medicinal products and substances. These constraints arise primarily from Mifepristone's function as a potent inhibitor of multiple Cytochrome P450 (CYP) enzymes, notably CYP3A4 and CYP2B6, which are responsible for metabolizing many other drugs.

Contraindicated and Restricted Combinations

Co-administration with CYP3A substrates that possess a narrow therapeutic index (e.g., Fentanyl, Quinidine, Tacrolimus, Simvastatin) is formally contraindicated as Mifepristone significantly increases their plasma concentration. The use of Mifepristone is also contraindicated with long-term systemic Glucocorticoids due to the risk of adrenal insufficiency resulting from its antiglucocorticoid activity. Furthermore, due to the risk of hemorrhage, the regimen is contraindicated in patients on Concurrent Anticoagulant Therapy.

Pharmacokinetic and Timing Constraints

Regulatory documentation specifies that Strong CYP3A Inducers (e.g., Rifampin, St. John's Wort) must be avoided as they decrease Mifepristone exposure, potentially reducing its effectiveness. Conversely, Strong CYP3A Inhibitors (e.g., Ketoconazole, Grapefruit Juice) increase Mifepristone exposure. For the intended use, there is a mandatory timing requirement that Misoprostol be administered 24 to 48 hours following the Mifepristone dose.

Mechanism of Action

Competitive Blockade of the Progesterone Receptor (PR)

Mifepristone's primary action is the competitive binding to the Progesterone Receptor (PR), functionally classifying it as an antiprogestin. This targeted molecular blockade prevents the natural hormone progesterone from stabilizing the uterine lining, thereby initiating a cascade that leads to the structural collapse and decidual breakdown of the endometrium.


Modulation via Prostaglandin Release and Muscle Tone

The degradation of the uterine lining triggers the localized, significant release of endogenous prostaglandins, powerful lipid mediators. This molecular cascade significantly increases the sensitivity of the myometrium (uterine smooth muscle), leading to increased contractility and cervical softening, resulting in physiological changes in muscle contractility.


️ Secondary Antagonism of the Glucocorticoid Receptor (GR)

Beyond its primary uterine effect, the drug also acts as a competitive antagonist at the Glucocorticoid Receptor (GR), the binding site for cortisol. This action modulates the HPA axis and limits the systemic metabolic effects of excessive cortisol activity at the tissue level, exhibiting a dual-receptor antagonism.

Dosage and Administration Information

Mifepristone is administered as an oral tablet, but its usage is dictated by the clinical goal, leading to two distinct administration protocols.

Acute, Short-Term Protocol

For the medical termination regimen, the medicine is administered as a single oral dose of 200 mg (Day 1). This single dose of Mifepristone is then followed by a separate medicine, a prostaglandin analogue, which is administered by the buccal, oral, or vaginal route usually 24 to 48 hours later. This full two-step process requires a mandatory follow-up assessment 7 to 14 days after the first dose to ensure the procedure is complete.


Chronic, Daily Protocol

Use of Mifepristone for managing Cushing's syndrome follows a chronic, daily regimen. Treatment begins with an oral dose of 300 mg once daily and must be taken with a meal. Tablets must be swallowed whole and should not be crushed. The dose is incrementally adjusted in 300 mg steps not more frequently than every 2 to 4 weeks, up to a maximum of 1200 mg per day. For patients with mild-to-moderate renal or hepatic impairment, the maximum daily dose is restricted to 600 mg.

Recent Clinical Evidence

Recent Clinical Evidence Overview

Clinical evidence for the substance (known as mifepristone) primarily comes from numerous Randomized Controlled Trials (RCTs) and meta-analyses conducted globally. The body of research has consistently focused on its use in combination with a prostaglandin analogue (typically misoprostol) for authorized indications.


Efficacy Findings

Research has explored the efficacy of the combined regimen in achieving complete outcomes without the need for surgical intervention. Studies have generally shown high rates of successful outcomes when used within the approved gestational limits, with success rates often reported in the range of 93% to 99% in clinical trials up to 70 days gestation.

Key areas of research include:

  • Gestational Limit: Early studies supported use up to 49 days of amenorrhea. Subsequent research, including pivotal trials, led regulatory bodies like the FDA and EMA to approve the combination regimen for use up to 70 days (10 weeks) of amenorrhea, reflecting the sustained efficacy observed in these trials.
  • Regimen Comparison: Clinical comparisons between the standard sequential regimen (mifepristone followed 24–48 hours later by misoprostol) and other timings, such as concurrent administration, have been evaluated. Studies comparing these protocols noted that the standard sequential regimen produced a significantly higher rate of complete outcomes than concurrent administration, which is why the sequential method remains the established protocol.

Safety and Tolerability

Research has examined the substance’s safety profile over many years of widespread use. The risk of serious complications, such as hemorrhage requiring blood transfusion or severe infection/sepsis, is noted in research as being low, occurring in approximately 1% or less of cases.

Long-term follow-up studies and systematic reviews have generally characterized the regimen as having a favorable safety profile when used according to approved clinical guidelines.

Frequently Asked Questions (FAQ)

Common questions about Мифегин (FAQ)

Q: Can taking Мифегин make me feel tired or dizzy?

A: Official regulatory information lists dizziness and weakness or tiredness as common adverse reactions associated with the drug’s use, often reported in over 15% of patients. Individuals should be aware of these systemic effects when using the medicine.


Q: Can I take Мифегин with common pain relievers like Tylenol or Ibuprofen?

A: Regulatory warnings highlight that Nonsteroidal Anti-inflammatory Drugs (NSAIDs) like Ibuprofen may theoretically interfere with the drug's intended action, though this risk has not been definitively established in all studies. Official patient information states that individuals should inform their healthcare provider of all pain relievers, including over-the-counter medicines, so that potential interaction risks can be managed.


Q: Are there any specific foods or drinks to avoid while using Мифегин?

A: Yes, regulatory documents specifically advise patients to avoid consuming grapefruit or grapefruit juice while using this medicine. This is because grapefruit can increase the concentration of the drug in the blood, potentially increasing the likelihood of adverse effects.


Q: Does the time of day I take Мифегин matter?

A: For the chronic daily protocol (Cushing's syndrome), official documents require the medicine to be taken once daily with a meal to maintain consistent blood levels. For the acute regimen, the second drug (Misoprostol) is administered 24 to 48 hours following the Mifepristone dose, as required by the established protocol.


Q: What should I do if I am already taking herbal supplements with Мифегин?

A: Official regulatory guidance states that individuals should inform their healthcare provider about all herbal products, vitamins, minerals, and supplements being used. Some supplements, such as St. John's Wort, are explicitly restricted because they can decrease the effectiveness of the medicine.


Q: Does Мифегин require a prescription from a doctor?

A: Yes. Mifepristone is classified as a prescription-only medicine. In the United States, it is available only through a restricted distribution system called the Mifepristone REMS Program (Risk Evaluation and Mitigation Strategy).


Q: How quickly does Мифегин start to take effect?

A: The medicine is rapidly absorbed after being taken orally. The highest concentration of the drug in the blood is typically reached within 45 to 90 minutes (0.75 to 1.5 hours) after ingestion. Its action in the body begins shortly after this absorption.


Q: How long does the primary effect of Мифегин usually last?

A: The active substance has a relatively long elimination half-life officially reported to be between 25 and 38 hours. Due to the way the drug and its active breakdown products bind to plasma proteins, its effects can be present in the body for up to 72 to 90 hours.


Q: Is Мифегин the same as other similar medicines I've heard about?

A: Мифегин contains the active ingredient Mifepristone, which is classified as a specific synthetic steroid that acts as both an antiprogestin and an antiglucocorticoid. This specific chemical and pharmacological profile is distinct from other medicines that may be used for related health purposes.


Q: Is it normal to have certain specific symptoms after taking Мифегин?

A: Yes. When used for the acute regimen, the process is expected to result in vaginal bleeding and uterine cramping, which are normal consequences of the medicine's action. Other common adverse reactions listed in official documents include nausea, vomiting, diarrhea, headache, and dizziness.


Q: What should I know about drug interactions with Мифегин?

A: It is important to know that Mifepristone is a potent inhibitor of certain liver enzymes (CYP3A4). This means it can significantly increase the blood concentration of many other medications, which may raise the risk of side effects or toxicity for those drugs. Official guidelines emphasize that concurrent medications should be discussed with a healthcare provider.


Q: Who is generally ineligible to use Мифегин?

A: Ineligibility is formally defined by several criteria, including confirmed ectopic pregnancy, an IUD in place, chronic adrenal failure or concurrent long-term steroid use, hemorrhagic disorders, or known inherited porphyrias. Eligibility for use is determined by a healthcare provider based on official product guidelines.


Q: Is Мифегин approved for use in all countries?

A: Mifepristone is listed on the World Health Organization's List of Essential Medicines and is approved for its indicated use in numerous countries worldwide. However, the specific rules for its use, such as gestational limits and distribution requirements (like REMS), are set by the individual national regulatory body in each country and can vary.


Q: What is the general difference between Мифегин and other options for the same purpose?

A: In the context of pregnancy termination, the regimen involving Mifepristone is a non-surgical method. This combination is recognized by the World Health Organization as an effective and safe option when used within approved gestational limits, distinguishing it from procedural options.


Q: How long has Мифегин been in use by patients?

A: The active ingredient, Mifepristone, has a history of clinical use spanning several decades globally. It was approved in France in 1987 and was approved by the U.S. FDA in September 2000, reflecting its long-established role in healthcare.


Q: Is there a generic version of Мифегин available?

A: Yes. The U.S. FDA approved the first generic version of Mifepristone tablets (200 mg) in April 2019, and other generic versions are available or have been approved for marketing, alongside the brand-name product.


Q: Can Мифегин be used by people of different age groups?

A: The safety and effectiveness of Mifepristone have not been established in the general pediatric population (children). The acute protocol is approved for adult and pregnant individuals aged 17 and younger who meet specific criteria, but use is generally not recommended in children for other indications.


Q: What is the regulatory status of Мифегин (e.g., restricted access)?

A: Mifepristone is subject to a Restricted Distribution System called the Mifepristone REMS Program (Risk Evaluation and Mitigation Strategy) in the United States. This regulatory framework imposes specific requirements on certified prescribers and dispensers to mitigate risks.


Q: What if I experience side effects that are not listed in the official information?

A: Official patient guides state that individuals should contact a healthcare provider immediately for medical advice regarding any unexpected or unlisted side effects or symptoms. For serious complications, patients are instructed to seek immediate medical attention, including going to an emergency room.


Q: Is Мифегин known to cause allergic reactions?

A: Hypersensitivity (allergic reaction) to Mifepristone or its components is an absolute contraindication for use. Patients are advised to seek immediate medical attention for symptoms such as rash, itching, hives, or swelling of the face, lips, tongue, or throat.


Q: Can Мифегин be taken by people with pre-existing health conditions?

A: Use of Mifepristone requires caution in patients with certain pre-existing conditions, including heart or blood vessel disease, uncontrolled high blood pressure, and severe kidney or liver disease. The decision regarding use is made by a healthcare provider following a full review of the patient's medical history.


Q: What is the role of the companion drug (if applicable) used with Мифегин?

A: For the acute regimen, Mifepristone is used in combination with a companion drug, typically Misoprostol. The role of the companion medicine is to cause the strong uterine contractions and cervical softening necessary to expel the contents of the uterus, completing the process initiated by Mifepristone.


Q: What are the main things users misunderstand about Мифегин?

A: The REMS program goals highlight the critical need for the patient to understand the risk of serious complications (e.g., severe bleeding or infection) and the mandatory nature of the follow-up assessment. The regimen is not complete until this mandatory follow-up check is performed.


Q: Does taking other medications reduce the effectiveness of Мифегин?

A: Yes. Medications classified as strong CYP3A Inducers (such as Rifampin or St. John's Wort) must be avoided because they can reduce the concentration of Mifepristone in the bloodstream. This reduced exposure may decrease the medicine's intended effectiveness.


Q: Is Мифегин safe to use if I have high blood pressure?

A: Patients with existing high blood pressure (hypertension) should use Mifepristone with caution. Official documents indicate the medicine may potentially worsen this condition or cause high blood pressure as a side effect. The decision for use is determined by a healthcare provider after a complete evaluation.


Q: What is the purpose of the Risk Evaluation and Mitigation Strategy (REMS) for this drug?

A: The purpose of the REMS program is to mitigate the risk of serious complications (such as infection or hemorrhage) by ensuring that prescribers are certified, patients are informed of the risks, and patients have access to emergency medical care if needed.


Q: Does the official guidance for Мифегин differ much between countries?

A: While the active ingredient is globally recognized and listed as an Essential Medicine by the WHO, the specific approved gestational limits and the distribution requirements can vary based on the regulations of national health authorities. These differences are set by the individual regulatory body in each country.


Q: Is it true that Мифегин can cause stomach upset?

A: Yes. Gastrointestinal issues are listed in official documents as very common adverse reactions. These often include nausea, vomiting, and diarrhea, which fall under the lay term 'stomach upset' and are reported in over 15% of patients.


Q: Are there different strengths or forms of Мифегин available?

A: Yes, the active ingredient, Mifepristone, is available in different strengths, typically the 200 mg tablet for the acute regimen and a 300 mg tablet for the chronic daily regimen. It is administered exclusively in the oral tablet dosage form.


Q: Can Мифегин affect the results of medical tests?

A: Yes. Because Mifepristone acts as an antiglucocorticoid, it modulates the HPA axis, leading to elevated levels of ACTH and cortisol. This means it can interfere with or affect the results of medical tests designed to measure these specific hormone levels.


Q: What is the difference in how Мифегин is used in different health settings?

A: The method of dispensing the drug is controlled by the REMS program, which specifies the health setting. Certified prescribers or certified pharmacies may dispense the drug in person or by using a shipping service with tracking information, depending on the regulatory system and location.


Q: What does the term 'pharmacodynamics' mean for Мифегин?

A: Pharmacodynamics refers to the effects of the drug on the body. For Mifepristone, this includes its primary action as a competitive blocker of the Progesterone Receptor (antiprogestin) and its secondary action as a competitive blocker of the Glucocorticoid Receptor (antiglucocorticoid).


Q: Are there studies comparing the effectiveness across different patient populations?

A: Regulatory documents indicate that the safety and effectiveness have not been established across all age groups, particularly in the general pediatric population. Studies primarily focus on the safety and efficacy of the regimen for its indicated uses within the approved patient populations and gestational limits.


Q: Do experts view Мифегин as a standard treatment option?

A: Yes. The active ingredient, Mifepristone, is listed on the World Health Organization’s (WHO) List of Essential Medicines. This designation confirms its recognized role as a necessary and standard therapeutic option for its indicated use in reproductive healthcare.


Q: Can Мифегин affect my ability to drive or operate machinery?

A: Official side effect data includes reports of common adverse reactions such as dizziness and weakness. Patients should be aware that these symptoms could potentially impair their ability to drive or operate machinery safely and should proceed with caution.


Q: What are the requirements for the healthcare provider who prescribes Мифегин?

A: Healthcare providers who prescribe Mifepristone are required to be certified in the drug's Risk Evaluation and Mitigation Strategy (REMS) program. They must also confirm the patient's appropriateness for the drug and ensure the patient has access to emergency medical care.


Q: What are the common reasons a doctor might not prescribe Мифегин?

A: Common reasons include the presence of an absolute contraindication (e.g., ectopic pregnancy, chronic adrenal failure, bleeding disorders) or the patient's inability to adhere to mandatory requirements. This includes the ability to return for follow-up or access emergency medical care if needed.

How should Мифегин be stored and disposed of?

The official regulatory documents provide clear constraints on how this medication must be stored and discarded to maintain its stability and ensure safety.

Storage Requirements

Domain Official Requirement
Temperature Store at room temperature, typically between 68 F and 77 F (20 C and 25 C).
Protection Keep the medication in its original closed container to protect it from heat, moisture, and direct light. Do not allow the medication to freeze.
Safety For accidental ingestion prevention, the drug must be kept out of the sight and reach of children at all times.

Disposal Instructions

Patients should not keep outdated or no longer needed medicine. Unused medication should be disposed of by consulting a healthcare professional for guidance or utilizing an authorized drug take-back program when available. Waste medication from professional facilities is typically collected and disposed of as controlled pharmaceutical waste, often through incineration or grinding and landfill, in accordance with local regulations.

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

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