U.S. Food and Drug Administration
FDA Consumer magazine
November-December 2000
Table of Contents
THE FOOD AND DRUG ADMINISTRATION approved mifepristone (trade name Mifeprex, previously known as RU-486) on September 28 for the termination of early pregnancy. Mifepristone blocks the hormone progesterone, which prepares the lining of the uterus for a fertilized egg and helps maintain pregnancy. Early pregnancy is defined as 49 days or less, counting from the beginning of the last menstrual period.
Mifepristone is part of an approved treatment regimen that calls for at least three visits to a doctor's office or clinic. On the first visit, the woman receives counseling and a medication guide. She then takes 600 milligrams of mifepristone (three 200 milligram pills) by mouth while in the doctor's office. Two days later, she returns to the physician and, if she is still pregnant, takes 400 micrograms (two 200-microgram pills) of misoprostol--again while in the doctor's office. Misoprostol, a prostaglandin previously approved by FDA for the treatment of ulcers, causes the uterine muscles to contract and end the pregnancy.
Approximately 14 days after the first visit, the woman returns to her doctor to determine whether the pregnancy has been terminated. The combination of mifepristone and misoprostol has been shown in studies to end pregnancy in about 92 to 95 percent of women. In the few cases where the pregnancy is not terminated by the drug treatment, the doctor then discusses options with the patient, including surgery to end the pregnancy. There is a chance that there may be birth defects if the pregnancy results in a live birth after treatment with mifepristone and misoprostol.
The medication guide given to each woman who is prescribed mifepristone fully explains how to take the drug, who should avoid taking it, and what side effects can occur. Both the doctor and patient must sign a Patient Agreement Form stating that the patient understands the benefits and risks of the treatment and has decided to end her pregnancy.
"The approval of mifepristone is the result of the FDA's careful evaluation of the scientific evidence related to the safe and effective use of this drug," said FDA Commissioner Jane E. Henney, M.D. "The FDA's review and approval of this drug has adhered strictly to our legal mandate and mission as a science-based public health regulatory agency."
FDA based its approval on data from clinical trials in the United States and France.
The drug's label emphasizes that most women using mifepristone will experience some side effects, mostly cramping and vaginal bleeding. Bleeding and spotting will typically last between 9 and 16 days. In about one out of 100 women, bleeding can be so heavy that surgery will be required to stop it. The drug's labeling also warns that mifepristone should not be used in women with certain conditions, including ectopic ("tubal") pregnancy. An ectopic pregnancy occurs when a fertilized egg begins to grow in one of the fallopian tubes that connect the ovaries to the uterus.
Mifepristone, not available in pharmacies, is distributed only to physicians who can accurately determine the duration of a patient's pregnancy and detect an ectopic pregnancy. Physicians who prescribe the drug must also be able to perform surgery in cases of an incomplete abortion or severe bleeding--or they must have made plans in advance to provide this care through other qualified physicians.
Mifepristone was developed by a French pharmaceutical firm and was first approved for use in France in 1988. Since then, more than 620,000 European women have taken mifepristone, known in Europe as RU 486, in combination with a prostaglandin (such as misoprostol) to terminate pregnancy. Mifepristone has also been approved in the United Kingdom, Sweden, and other countries.
Mifepristone's sponsor is a New York-based nonprofit group, the Population Council. The drug will be distributed in the United States by Danco Laboratories, LLC, New York.
More detailed information about mifepristone is available on FDA's Web site at www.fda.gov/cder/drug/infopage/mifepristone/.
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