Mifepristone

Pronunciation: miff-ee-pris-tone
Generic name: mifepristone
Brand names: Mifeprex, Korlym
Dosage form: oral tablet
Drug classes: Progesterone receptor modulators, Uterotonic agents

Medically reviewed by Carmen Pope, BPharm. Last updated on Aug 2, 2024.

What is mifepristone?

Mifepristone (Mifeprex) is an oral tablet that may be used with misoprostol tablets to end a pregnancy that is 10 weeks or less (70 days or less since the start of your last period).

Another brand of mifepristone called Korlym may be used to treat high blood sugar caused by high cortisol levels in adults with Cushing’s syndrome who have type 2 diabetes or glucose intolerance and have failed surgery or cannot have surgery.

• For this use, mifepristone is given daily, and females must avoid becoming pregnant.
• Mifepristone should not be used by people with type 2 diabetes mellitus that is not caused by Cushing’s syndrome.

Mifepristone was first FDA-approved on September 28, 2000, as the brand Mifeprex. Korlym was FDA-approved on February 17, 2012.

Mifepristone and misoprostol for pregnancy termination

Mifepristone and misoprostol are taken together to terminate a pregnancy (also called a medical abortion).

• Mifepristone prevents a pregnancy from continuing by blocking progesterone, a hormone essential for pregnancy.
• Misoprostol causes the cervix to soften and the uterus to contract. This expels the pregnancy.
• The Mifeprex brand of mifepristone is only available through a restricted program called the Mifeprex REMS.
  • This is to ensure you are fully informed and aware of all the possible side effects that can happen with mifepristone and to provide you with the Mifeprex Medication Guide.

Dosage of mifepristone and misoprostol for pregnancy termination

The usual dosage of mifepristone and misoprostol to terminate a pregnancy is mifepristone 200 mg (1 tablet) on Day 1, followed 24 to 48 hours later by misoprostol 800 mcg (four 200 mcg tablets), which is placed in the cheek pouch (buccally).

• The mifepristone tablet is swallowed whole.
• The misoprostol tablets are placed in the cheek pouch (buccally). This means you put them between your top lip and gum. Place 2 misoprostol tablets in one cheek pouch and two in the other. Leave them there for 30 minutes and then swallow anything left over with a drink of water or another liquid.
• The medicines may not work as well if you do not follow your healthcare provider's instructions properly.

Mifepristone side effects when used to terminate a pregnancy

Common side effects of mifepristone when used to terminate a pregnancy are:

• feeling sick (nausea)
• feeling tired or weak
• cramping
• vaginal bleeding
• fever/chills
• vomiting
• headache
• diarrhea
• dizziness.

If you are not already bleeding from your vagina after taking mifepristone, you will begin to bleed once you take misoprostol.

• Bleeding or spotting can be expected for an average of 9 to 16 days and may last up to 30 days.
• Your bleeding may be similar to, or greater than, a normal heavy period. You may see blood clots and tissue. This is an expected part of passing the pregnancy.

The combination of mifepristone and misoprostol often causes cramps, nausea, diarrhea, and other symptoms. Your healthcare provider may send you home with medicines for these symptoms.

Serious side effects and warnings

Mifepristone carries a Boxed Warning for serious and sometimes fatal infections and bleeding.

Serious and sometimes fatal infections and bleeding are rare when mifepristone is used to terminate a pregnancy, but it is important to know that these can happen. In certain circumstances, serious bacterial infections can present without symptoms typical of an infection, for example, without fever or without shaking, chills, or gastrointestinal symptoms.

Cramping and vaginal bleeding are expected with this treatment. Usually, these symptoms mean the treatment is working. But sometimes you may get cramping and bleeding but still be pregnant. Prolonged heavy bleeding may be a sign of an incomplete abortion or other complications and further medical or surgical intervention may be required. Contact your healthcare provider right away if you have:

• Heavy bleeding, especially if you bleed enough to soak through two thick full-size sanitary pads per hour for two consecutive hours or if you are concerned about heavy bleeding. In about 1 out of 100 women, bleeding can be so heavy that it requires a surgical procedure (surgical aspiration or D&C)
• Abdominal pain, abdominal discomfort, or “feeling sick”, including weakness, nausea, vomiting, or diarrhea, with or without fever, more than 24 hours after taking mifepristone. These symptoms may be a sign of a serious infection or another problem (including an ectopic pregnancy, a pregnancy outside the womb)
• A high fever (100.4°F or higher) that lasts for more than 4 hours. Fever may be a symptom of a serious infection or another problem.

If you cannot reach your healthcare provider for any of these problems, go to the nearest hospital emergency room. Take your mifepristone (Mifeprex) Medication Guide with you or tell them that you have recently taken medicine to terminate a pregnancy.

Rhesus immunization. Using mifepristone requires the same preventive measures as those taken before and during surgical abortion to prevent rhesus immunization.

When used for a medical abortion, mifepristone is not approved for ending pregnancies that are further along than 10 weeks.

These are not all the possible side effects of mifepristone when used to terminate a pregnancy. Call your healthcare provider for medical advice about any side effects that bother you or do not go away. You may report side effects to the FDA at 1-800-FDA-1088.

Before taking mifepristone for a pregnancy termination

Some women should not take mifepristone (Mifeprex) to terminate a pregnancy, including women who:

• have a pregnancy that is more than 70 days (10 weeks). Your healthcare provider may do a clinical examination, an ultrasound examination, or other testing to determine how far along you are in pregnancy
• are using an IUD (intrauterine device or system). It must be taken out before you take mifepristone
• have been told by your healthcare provider that you have a pregnancy outside the uterus (also called an ectopic pregnancy)
• are allergic to mifepristone, misoprostol, Mifeprex, Korlym, Cytotec, or Arthrotec
• have problems with their adrenal glands (chronic adrenal failure).
• take a medicine to thin your blood, such as dabigatran or warfarin
• have a bleeding problem
• have porphyria
• take certain steroid medicines.

Tell your healthcare provider if you:

• cannot follow up within approximately 7 to 14 days of your first visit
• are breastfeeding
• are taking medicines, including prescription and over-the-counter medicines, vitamins, and herbal supplements (see interactions below).

Ask your healthcare provider if you are not sure about all your medical conditions before taking mifepristone.

How long does it take a pregnancy to be expelled after mifepristone and misoprostol?

Most pregnancies are passed 2 to 24 hours after taking the misoprostol tablets.

• When the pregnancy is passed from the uterus, you will have bleeding and cramping that will likely be heavier than your usual period.
• About 2 to 7 out of 100 women taking Mifeprex will need a surgical procedure because the pregnancy did not completely pass from the uterus or stop bleeding.
• Follow your healthcare provider's advice about what to do if you have severe side effects.

You will need to talk to a healthcare provider in 7 to 14 days for a follow-up assessment to confirm that the pregnancy has been terminated.

• Prolonged heavy vaginal bleeding is not proof of a complete abortion.
• If the treatment fails and the pregnancy continues, the risk of fetal malformation is unknown.
• It is recommended that ongoing pregnancy be managed by surgical termination.

Mifepristone court rulings

Although FDA regulations allow certified healthcare professionals and pharmacies to dispense mifepristone and misoprostol for medical abortion both in healthcare facilities and by telehealth and mail, certain state laws may not allow this.

For example, Louisiana has passed a bill that classifies mifepristone and misoprostol as dangerous controlled substances which, once signed, would mean anyone possessing these abortion pills without a prescription could face jail time and fines. Most abortions are already illegal in Louisiana.

Related/similar drugs

dexamethasone, cyproheptadine, Decadron, oxytocin, Pitocin, carboprost, Hemabate

Mifepristone for Cushing's syndrome

The Korlym brand of mifepristone is FDA approved to treat high blood sugar caused by high cortisol levels in adults with Cushing’s syndrome who have type 2 diabetes or glucose intolerance and have failed surgery or cannot have surgery.

• When used to treat Cushing’s syndrome, mifepristone competes with cortisol to bind to the cortisol receptor, which leads to decreased cortisol activity without a decrease in cortisol levels. This can lead to decreases in blood sugar levels, weight loss, and a reduction in the amount of antidiabetic medications required.

Mifepristone side effects when used to treat Cushing’s syndrome

The most common side effects of daily mifepristone in people with Cushing's syndrome include:

• nausea or vomiting
• fatigue
• headache
• low potassium in your blood
• joint pain
• swelling of your arms and legs (peripheral edema)
• high blood pressure
• dizziness
• decreased appetite
• thickening of the lining of the uterus (endometrial hypertrophy).

Tell your doctor if you have any side effect that bothers you or that does not go away.

Serious side effects and warnings

Mifepristone can cause serious side effects when taken daily to treat Cushing’s syndrome, such as pregnancy loss, adrenal insufficiency, low potassium, vaginal bleeding, menstrual cycle changes, QT interval prolongation, and a deterioration in other conditions treated by corticosteroids.

Pregnancy loss. When used for non-pregnancy related conditions, such as for Cushing’s syndrome, mifepristone should not be used during pregnancy, and women who can become pregnant must:

• have a negative pregnancy test before starting mifepristone or before restarting it if you stopped taking it for more than 14 days
• use a non-hormonal form of birth control while taking mifepristone and for 1 month after stopping it.

Reduced effects of adrenal hormones (adrenal insufficiency). Long-term use of mifepristone stops an adrenal hormone in your body called cortisol from working. Tell your doctor right away if you have any symptoms of adrenal insufficiency. Symptoms may include:

• unusual tiredness or weakness
• nausea
• fatigue
• low blood pressure (hypotension)
• low blood sugar (hypoglycemia).

Low blood potassium (hypokalemia). Your doctor should check the potassium level in your blood before you start taking mifepristone and while you take it. Tell your doctor if you have any signs of low potassium. Signs may include muscle weakness, aches, cramps, or abnormal or irregular heartbeats (palpitations).

Vaginal bleeding. Long-term mifepristone may cause the lining of your uterus to become thick and may cause your uterus to bleed. Tell your doctor right away about any bleeding from your vagina that is not normal for you.

Disruption of the menstrual cycle. Your periods may be longer or shorter than usual and you may experience more blood loss.

Problems with the electrical system of your heart (QT interval prolongation).

Worsening symptoms of other medical problems that are being treated with corticosteroids when you take corticosteroids and mifepristone at the same time. Mifepristone antagonizes the effects of corticosteroids.

These are not all the possible side effects of mifepristone. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Before taking mifepristone for Cushing’s syndrome

Do not take mifepristone if you:

• are allergic to mifepristone or any of the inactive ingredients in Korlym (see ingredients below)
• are pregnant
• are taking certain medications such as statins, cyclosporine, ergots, fentanyl, corticosteroids, and others (see interactions below)
• are a woman who still has her uterus (womb) and has unexplained bleeding from your vagina or known changes in the cells lining your uterus (endometrial hyperplasia) or cancer of the lining of your uterus (endometrial cancer).

Tell your healthcare provider if you:

• are pregnant or planning to become pregnant
• have low potassium in your blood (hypokalemia)
• have or have had a bleeding problem or are taking medicines to thin your blood
• have or have had heart problems
• have had an organ transplant
• have been taking medicines called corticosteroids (cortisone, dexamethasone, methylprednisolone, prednisolone, prednisone)
• are breastfeeding or planning to breastfeed.

Pregnancy

Mifepristone should not be used in women with Cushing’s syndrome who are pregnant because it will cause loss of the unborn baby. There is no data regarding the risk of birth defects in women who have inadvertently been exposed to mifepristone while pregnant.

If you can become pregnant, you will need to have a negative pregnancy test before starting this treatment and use a non-hormonal form of birth control while taking mifepristone and for 1 month after stopping it.

Talk to your doctor about how to prevent pregnancy. Tell your doctor right away if you think you may be pregnant.

Breastfeeding

Mifepristone can pass into your breast milk. The effect of the mifepristone on the breastfed infant or milk production is unknown.

How should I take mifepristone for Cushing's syndrome?

Take mifepristone exactly as your doctor tells you.

For Cushing's syndrome, mifepristone is usually taken 1 time each day.

• The usual starting dose is 300 mg by mouth (orally) once a day.
• Take it with food.
• Swallow the tablets whole. Do not split, crush, or chew the tablets. If you cannot swallow the tablets whole, tell your doctor.
• Your healthcare provider may increase your dosage of mifepristone in 300mg increments every 2 to 4 weeks to a maximum daily dose of 1200 mg once a day (not exceeding 20 mg/kg a day or 600 mg/day for those with kidney or liver disease).

What should I avoid while taking mifepristone?

Do not drink grapefruit juice while you take mifepristone. Grapefruit juice may increase the amount of mifepristone in your blood and increase your risk of side effects.

What happens if I am still pregnant after taking mifepristone with misoprostol treatment?

If you are still pregnant, your healthcare provider will talk with you about a surgical procedure to end your pregnancy.

• In many cases, this surgical procedure can be done in the office/clinic.
• The chance of birth defects if the pregnancy is not ended is unknown.

Will I be able to get pregnant again after having a medical abortion?

There is no reason why taking mifepristone and misoprostol for a medical abortion will affect your future fertility and the ability to become pregnant, although animal studies have shown there may be some disruption to your menstrual cycle for up to 3 weeks after taking the combination.

• Another pregnancy can occur following a medical abortion before your periods resume.
• You can start using contraception as soon as the pregnancy expulsion has been confirmed, or before you resume sexual intercourse.

What other medications will affect mifepristone?

Tell your doctor about all of the medicines you take, including prescription and nonprescription medicines, vitamins, and herbal supplements.

Using mifepristone daily (Korlym brand) with certain other medicines can affect each other. Especially tell your doctor if you take medicines to treat:

• fungal infections (such as ketoconazole)
• cyclosporine (Gengraf, Neoral, Restasis, Sandimmune)
• depression
• dihydroergotamine (Migranal) or ergotamine (Ergomar, Migergot)
• fentanyl (Abstral, Actiq, Duragesic, Fentora, Lazanda, Onsolis, Sublimaze, Subsys)
• HIV infection
• Hepatitis C infection
• certain bacterial infections
• high blood pressure, such as sotalol
• hormonal contraceptives
• pimozide (Orap)
• quinidine (Nuedexta) or other Q-T interval prolonging medications
• sirloimus (Rapamune, Torisel) or tacrolimus (Prograf, Protopic)
• statin medications such as simvastatin (Zocor, Vytorin, Simcor) or lovastatin (Mevacor, Altoprev, Advicor)
• steroid medicines such as prednisone
• thyroid hormones.

Medications such as ketoconazole, nefazodone, ritonavir, and other strong CYP3A inhibitors may increase blood levels of mifepristone that is used as part of a medical abortion regimen and should only be used together when necessary. A maximum dose of 900 mg of mifepristone should be adhered to. If a strong CYP3A inhibitor is started in a person already taking mifepristone, the dosage may need to be reduced.

• Do not use mifepristone with CYP3A inducers, such as glucocorticoids, rifampin, carbamazepine, phenobarbital, phenytoin, and grapefruit juice.

If you are unsure, ask your doctor or pharmacist for a list of these medicines. Know the medicines you take. Keep a list of them to show to your doctor and pharmacist. See the prescribing information for a full list of interactions.

Storage

Store mifepristone tablets at room temperature, between 68°F to 77°F (20°C to 25°C).

Keep out of the reach of children.

Mifepristone ingredients

Mifeprex ingredients

Active ingredient: mifepristone 200mg

Inactive ingredients: colloidal silica anhydrous, corn starch, povidone, microcrystalline cellulose, and magnesium stearate.

Available as 200 mg tablets.

Korlym ingredients

Active ingredient: mifepristone 300mg

Inactive ingredients: silicified microcrystalline cellulose, sodium starch glycolate, hydroxypropyl cellulose, sodium lauryl sulfate, magnesium stearate, hypromellose, titanium dioxide, triacetin, D&C yellow 10 aluminum lake, polysorbate 80, and FD&C yellow 6 aluminum lake.

Available as 300 mg tablets.

Manufacturer

Mifeprex: Danco Laboratories, LLC.

Korlym: Corcept Therapeutics Incorporated.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer