Mifepristone is a prescription medication primarily used for medical termination of early pregnancy and, in some cases, for managing certain endocrine or gynecological conditions. When taken as part of a two-drug regimen with misoprostol, it effectively ends an early pregnancy without surgery. Beyond reproductive care, mifepristone may also be used in the treatment of Cushing’s syndrome, where it helps control high cortisol levels in the body. Understanding what mifepristone does, how it works and what to expect can help patients use it safely under medical supervision.

What is Mifepristone?

Mifepristone (brand name Mifeprex or Korlym) is a synthetic steroid that blocks the action of the hormone progesterone, which is essential for maintaining pregnancy. It belongs to a class of drugs known as antiprogestins.

The U.S. Food and Drug Administration (FDA) first approved mifepristone in 2000 for medical termination of intrauterine pregnancies up to 70 days of gestation. Later, it was also approved under the brand name Korlym to control high blood sugar in adults with Cushing’s syndrome who have type 2 diabetes or glucose intolerance (FDA, 2019).

What does Mifepristone do?

Mifepristone is primarily used for two major purposes:

1. Medical abortion: In combination with misoprostol, mifepristone helps end an early pregnancy without surgery. It’s prescribed when the pregnancy is less than 10 weeks. Mifepristone alone prepares the uterus, and misoprostol completes the process by inducing uterine contractions to expel pregnancy tissue.
2. Cushing’s syndrome: For patients with endogenous Cushing’s syndrome, mifepristone helps reduce high blood sugar levels caused by excessive cortisol. It does so by blocking cortisol’s effects at its receptor sites rather than lowering cortisol production itself.

Effectiveness:

• When used correctly with misoprostol, mifepristone is over 95% effective for ending an early pregnancy (WHO, 2023).
• For Cushing’s syndrome, studies show that mifepristone significantly improves glucose control and reduces clinical symptoms (NIH, 2022).

How does Mifepristone work?

Mifepristone works by blocking hormone receptors that are essential for maintaining pregnancy and regulating metabolism. Its action depends on the condition being treated:

• In early pregnancy: Mifepristone binds to progesterone receptors, preventing the hormone from supporting the uterine lining. Without progesterone’s effects, the uterine lining breaks down, and the pregnancy cannot continue. This makes the uterus more sensitive to misoprostol, which triggers contractions to complete the abortion process (NIH, 2023).
• In Cushing’s syndrome: Mifepristone blocks the glucocorticoid receptor, reducing the effects of excess cortisol in the body. This helps control symptoms like high blood sugar, weight gain, and high blood pressure (Mayo Clinic, 2023).

Because mifepristone directly interferes with hormone receptors, its effects can be powerful and must always be monitored by a qualified healthcare provider.

In medical settings, it’s noted that when used in combination with a prostaglandin analogue, the coordinated pharmacologic action significantly enhances treatment success and reduces incomplete outcomes.

Mifepristone side effects

Like all medications, mifepristone can cause side effects, though many are temporary and manageable. The type and severity often depend on why the drug is being used.

Common side effects (in pregnancy termination):

• Cramping and vaginal bleeding
• Nausea, vomiting or diarrhea
• Fatigue or mild dizziness
• Headache

Less common or serious effects:

• Prolonged or heavy bleeding
• Signs of infection (fever, pelvic pain, foul-smelling discharge)
• Allergic reactions (rash, swelling, or breathing difficulty)

For Cushing’s syndrome:

• Nausea, loss of appetite
• Low potassium levels
• Fatigue or joint pain
• Irregular menstruation (in women)

Seek urgent medical care if:

• You have continuous heavy bleeding (soaking more than two pads per hour for over two hours).
• You develop a high fever or feel unwell after the abortion process.
• You have severe or persistent pain that doesn’t respond to over-the-counter pain relief

For patients with Cushing’s syndrome, side effects may include fatigue, low potassium levels, or adrenal insufficiency symptoms, which should be discussed with a doctor before starting treatment.

In clinical experience, most side effects are transient and manageable, often related to the hormonal changes induced by the medication.

Mifepristone dosage

Mifepristone is taken by mouth.

• For early pregnancy termination: It’s typically given as a single dose, followed by misoprostol 24 to 48 hours later. Patients usually receive both medications under medical supervision, with clear instructions for home use and follow-up care.
• For Cushing’s syndrome: The dosage and duration are highly individualized, starting low and adjusted by the physician based on blood sugar control and symptom improvement.

Monitoring: Patients on mifepristone should be closely monitored for:

• Signs of infection or incomplete abortion (in reproductive use)
• Blood potassium levels and thyroid function (in Cushing’s use)
• Menstrual cycle changes and overall physical recovery

Clinicians typically follow standardized dosing protocols, as even slight variations in dose or timing can influence both safety and effectiveness.

Does Mifepristone Have a Generic Version?

Yes. Generic mifepristone has been FDA-approved and is considered therapeutically equivalent to its brand-name counterparts, Mifeprex and Korlym. Generic versions undergo the same quality, safety, and efficacy testing as brand-name drugs, ensuring they work just as effectively.

Because of regulatory restrictions and safety monitoring, mifepristone is distributed through certified healthcare settings and pharmacies under a Risk Evaluation and Mitigation Strategy (REMS) program (FDA, 2023). This ensures that patients receive proper counseling and follow-up after taking the medication.

Conclusion

Mifepristone is a well-studied, effective medication that plays an important role in reproductive and hormonal health. Whether used for early medical abortion or to control blood sugar in Cushing’s syndrome, it must always be prescribed and monitored by a healthcare professional.

Patients considering or using mifepristone should maintain open communication with their doctor, report any unusual symptoms promptly, and attend follow-up visits as recommended. When prescribed appropriately and monitored carefully, mifepristone provides a safe, effective, and non-surgical option that has helped millions of patients worldwide.

References

1. U.S. Food and Drug Administration (FDA). (2019). Mifepristone Information. https://www.fda.gov
2. Mayo Clinic. (2023). Mifepristone (Oral Route). https://www.mayoclinic.org
3. National Institutes of Health (NIH). (2023). Mifepristone: MedlinePlus Drug Information. https://medlineplus.gov