DrugindexOnline^{2nd edition}

Some commonly used brand names are:

In the U.S.—

• Mifeprex

Other commonly used names are

RU 486

Category

• Abortifacient

Description

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:

• Oral
• Tablets (U.S.)

Before Using This Medicine

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:

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

Pregnancy—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.

Breast-feeding—It is unknown whether mifepristone is distributed in the breast milk. It may be necessary for you to stop breast-feeding during treatment. Be sure you have discussed the risks and benefits of this treatment with your doctor.

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:

• Adrenal failure—Mifepristone may not work appropriately

• Bleeding problems—May cause excessive vaginal bleeding

• Diabetes or
• Heart disease or
• High blood pressure or
• Kidney disease or
• Liver disease or
• Lung disease
• Women older than 35 years of age who smoke cigarettes (10 or more a day)—You should use caution if you have any of these chronic conditions and let your doctor know before beginning treatment with this medicine.

• Ectopic pregnancy (e.g., a pregnancy that develops in fallopian tubes instead of the uterus) 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

Proper Use of This Medicine

Dosing—

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

Precautions While Using This Medicine

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 (i.e., soaking through two thick full-size sanitary pads per hour for two consecutive hours) .

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.

You should check with your physician immediately if signs or symptoms of serious infection (i.e., continuing fever [ge ] 100.4 °F, severe stomach pain, pelvic tenderness, weakness, nausea, vomiting, diarrhea, or abnormally fast heartbeat) occur.

Side Effects of This Medicine

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.

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

Developed: 10/13/2000
Revised: 09/14/2005

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