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Mifepristone (Systemic)

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Mifepristone (Systemic)

US Brand Names

• Mifeprex

Other commonly used names are

RU 486


Mifepristone (mif-i-PRIS-tone) is used to end a pregnancy that is less than 49 days' in duration. It works by stopping the supply of hormones that maintains the interior of the uterus. Without these hormones, the uterus cannot support the pregnancy and the contents of the uterus are expelled.

This medicine is available only with your doctor's prescription, in the following dosage form:


    • Tablets (U.S.)

Special Considerations

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For mifepristone, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to mifepristone, misoprostol or any other prostaglandins.


Mifepristone is used to terminate an early pregnancy. Fetal deformities may result if a pregnancy is allowed to continue following a failed attempt at medical termination.


It is unknown whether mifepristone is distributed in the breast milk.

Other medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking mifepristone, it is especially important that your doctor and pharmacist know if you are taking any of the following:

    • Carbamazepine (e.g., Tegretol) or

    • Dexamethasone (e.g., Decadron) or

    • Phenobarbital (e.g., Luminal) or

    • Phenytoin (e.g., Dilantin) or

    • Rifampin (e.g., Rifadin) or

    • St. John's Wort - May decrease the concentration of mifepristone in the blood

    • Erythromycin (e.g., E-Mycin) or

    • Grapefruit juice or

    • Itraconazole (e.g., Sporanox) or

    • Ketoconazole (e.g., Nizoral) - May increase the concentration of mifepristone in the blood

    • Anticoagulants, such as warfarin (e.g., Coumadin) - May increase the risk of bleeding

    • Corticosteroids (cortisone-like medicine)-Mifepristone may not work as well

Other medical problems

The presence of other medical problems may affect the use of mifepristone. Make sure you tell your doctor if you have any other medical problems, especially:

    • Bleeding problems-May cause excessive vaginal bleeding

    • Adrenal failure - Mifepristone may not work appropriately

    • Ectopic pregnancy or

    • Lower abdominal mass - Mifepristone will not terminate an ectopic pregnancy

    • An intrauterine device (IUD) that is still in the uterus - Must be removed before mifepristone therapy is started

    • Porphyria, inherited

    • Anemia, severe or

    • Poor blood circulation or

    • Inability of blood to clot properly-Mifepristone causes heavy bleeding in a small portion of users, this may be intensified in patients with bleeding disorders



    • To terminate a pregnancy of 49 days or less duration:

      o For oral dosage form (tablets):

        Adults-600 milligrams (mg) (three 200 mg tablets) as a single oral dose followed two days later by 400 micrograms (mcg) (two 200 mcg tablets) of misoprostol as a single oral dose as needed.


You must have 3 visits to your physicians office during the treatment procedure. It is extremely important that you attend all three visits.

Check with your physician if the vaginal bleeding becomes severe or seems to last longer than expected.

You may need to have a surgical procedure to stop excessive vaginal bleeding or to terminate a pregnancy that was not terminated with the medical treatment procedure.

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

Less common

Excessively heavy vaginal bleeding; unusual tiredness or weakness.

Incidence not known

chest pain or discomfort; confusion; cough or hoarseness; fast, weak pulse; fever or chills; lower back or side pain; pain or discomfort in arms, jaw, back or neck; painful or difficult urination; pale, cold, clammy skin; shortness of breath; sudden increase in abdominal or shoulder pain; sweating; unusual or large amount of vaginal bleeding.

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome.

More common

Abdominal pain or uterine cramping; back pain; diarrhea; dizziness; headache; nausea or vomiting.

Less common

Acid or sour stomach; anxiety; belching; cough; fainting or light-headedness when getting up from a lying or sitting position; fever; flu-like symptoms; headache; heartburn; increased clear or white vaginal discharge; indigestion; itching of the vagina or genital area; lack or loss of strength; pain during sexual intercourse; pain or tenderness around eyes and cheekbones; pale skin; shaking chills; shortness of breath or troubled breathing; sleeplessness or trouble sleeping; stomach discomfort, upset, or pain; tightness of chest or wheezing; troubled breathing, exertional; unusual bleeding or bruising; stuffy or runny nose.

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

September 30, 2002

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