February 10, 2016
Recommended Topic Related To:

Mifeprex (RU486)

"Risk factors for repeat pregnancy terminations include teenage pregnancy, social deprivation, two or more previous live births or miscarriages at the time of the initial termination, and the use of posttermination contraception with implants and "...



Mifeprex (RU486) Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 9/18/2015

Mifeprex (mifepristone) is a synthetic steroid indicated for the medical termination of intrauterine pregnancy through 49 days of pregnancy. Mifeprex Tablets are available in generic form. Side effects of Mifeprex include pelvic pain or cramps, nausea, diarrhea, stomach pain, dizziness, tired feeling, or back pain. Other side effects of Mifeprex include allergic reactions such as closing of the throat, swelling of the lips, and tongue, or face. Seek emergency medical attention if any of these allergic reactions occur.

Mifeprex is available in 200mg strength tablets. Treatment with Mifeprex and misoprostol for the termination of pregnancy requires three office visits. Patients must understand the necessity of completing the treatment schedule including a follow-up visit approximately 14 days after taking Mifeprex. Another pregnancy can occur following termination of pregnancy and before resumption of normal menses. Breast feeding women should consult with their health care provider to decide if they should discard their breast milk for a few days following administration of the medications.

Our Mifeprex (mifepristone) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is Patient Information in Detail?

Easy-to-read and understand detailed drug information and pill images for the patient or caregiver from Cerner Multum.

Mifeprex (RU486) in Detail - Patient Information: Side Effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Bleeding and spotting are normal side effects of Mifeprex. Bleeding may be slightly heavier than a normal period. Call your doctor right away if you bleed enough to soak through 2 full-size sanitary pads per hour for 2 hours in a row.

Call your doctor at once if you have any other serious side effect, such as:

  • general ill feeling and fast heart rate;
  • a fever higher than 100.4 degrees F (38 degrees C);
  • severe pelvic pain or tenderness;
  • severe or ongoing nausea, vomiting, diarrhea, weakness; or
  • no vaginal bleeding at all after taking Mifeprex.

Less serious side effects may include:

  • mild pelvic pain or cramps;
  • mild nausea or diarrhea, mild stomach pain;
  • dizziness, tired feeling; or
  • back pain.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Mifeprex (RU486) (Mifepristone (RU486))

What is Patient Information Overview?

A concise overview of the drug for the patient or caregiver from First DataBank.

Mifeprex (RU486) Overview - Patient Information: Side Effects

SIDE EFFECTS: See also Warning section.

Nausea, vomiting, diarrhea, weakness, or dizziness may occur. If these effects persist longer than the first 24 hours after taking the second drug (misoprostol), seek immediate medical attention because they can be signs of a serious medical problem.

Bleeding and cramping are expected during this treatment. Usually, the symptoms mean the drugs are working. However, sometimes you can have cramps and bleeding and still be pregnant. Therefore, you must return for all 3 of your doctor visits. Nausea and cramping may worsen in the 24 hours after you take the second drug (misoprostol). Your doctor may direct you to take other medication to help with these symptoms. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Bleeding and spotting may last up to 30 days and may be much heavier than a normal period. In very few cases, this bleeding will need to be stopped by surgery. Seek immediate medical attention if you bleed enough to soak through 2 thick, full-size sanitary pads each hour for 2 hours in a row, or if you are concerned about heavy bleeding.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Seek immediate medical attention if you have any of these unlikely but very serious side effects: fever of 100.4 degrees F (38 degrees C) or higher, fainting, fast heartbeat, stomach/abdominal pain or tenderness.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Read the entire patient information overview for Mifeprex (RU486) (Mifepristone (RU486))

What is Prescribing information?

The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.

Mifeprex (RU486) FDA Prescribing Information: Side Effects
(Adverse Reactions)


The treatment procedure is designed to induce the vaginal bleeding and uterine cramping necessary to produce an abortion. Nearly all of the women who receive Mifeprex and misoprostol will report adverse reactions, and many can be expected to report more than one such reaction. About 90% of patients report adverse reactions following administration of misoprostol on day three of the treatment procedure. Those adverse events that occurred with a frequency greater than or equal to 1% in the U.S. and French trials are shown in Table 3.

Vaginal bleeding and uterine cramping are expected consequences of the action of Mifeprex as used in the treatment procedure. Following administration of mifepristone and misoprostol in the French clinical studies, 80 to 90% of women reported bleeding more heavily than they do during a heavy menstrual period (see WARNINGS, Vaginal Bleeding). Women also typically experience abdominal pain, including uterine cramping. Other commonly reported side effects were nausea, vomiting and diarrhea. Some adverse reactions reported during the four hours following administration of misoprostol were judged by women as being more severe than others: the percentage of women who considered any particular adverse event as severe ranged from 2 to 35% in the U.S. and French trials. After the third day of the treatment procedure, the number of reports of adverse reactions declined progressively in the French trials, so that by day 14, reports were rare except for reports of bleeding and spotting.

Table 3: Type of Reported Adverse Events Following Administration of Mifepristone and Misoprostol in the U.S. and French Trials* (percentages)

  U.S. Trials French Trials
Abdominal Pain (cramping) 96 NA
Uterine cramping NA 83
Nausea 61 43
Headache 31 2
Vomiting 26 18
Diarrhea 20 12
Dizziness 12 1
Fatigue 10 NA
Back pain 9 NA
Uterine hemorrhage 5 NA
Fever 4 NA
Viral infections 4 NA
Vaginitis 3 NA
Rigors (chills/shaking) 3 NA
Dyspepsia 3 NA
Insomnia 3 NA
Asthenia 2 1
Leg pain 2 NA
Anxiety 2 NA
Anemia 2 NA
Leukorrhea 2 NA
Sinusitis 2 NA
Syncope 1 NA
Endometritis/Salpingitis/Pelvic Inflammatory Disease 1 NA
Decrease in hemoglobin greater than 2 g/dL NA 6
Pelvic pain NA 2
Fainting NA 2
*Only adverse reactions with incidence 1% are included.

Postmarketing Experience

The following adverse reactions have also been reported during post-approval use of Mifeprex and misoprostol. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. No causal relationship between these events and Mifeprex and misoprostol has been established:

Allergic reaction (including rash, hives, itching), hypotension (including orthostatic), lightheadedness, loss of consciousness, post-abortal infection (including endomyometritis, parametritis), ruptured ectopic pregnancy, shortness of breath, and tachycardia (including racing pulse, heart palpitations, heart pounding).

Read the entire FDA prescribing information for Mifeprex (RU486) (Mifepristone (RU486))

Mifeprex - User Reviews

Mifeprex User Reviews

Now you can gain knowledge and insight about a drug treatment with Patient Discussions.

Here is a collection of user reviews for the medication Mifeprex sorted by most helpful. Patient Discussions FAQs

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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