August 30, 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 following adverse reactions are described in greater detail in other sections:

Clinical Trials Experience

Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice.

Information presented on common adverse reactions relies solely on data from US studies, because rates reported in non-US studies were markedly lower and are not likely generalizable to the US population. In three US clinical studies totaling 1,248 women through 70 days gestation who used mifepristone 200 mg orally followed 24-48 hours later by misoprostol 800 mcg buccally, women reported adverse reactions in diaries and in interviews at the follow-up visit. These studies enrolled generally healthy women of reproductive age without contraindications to mifepristone or misoprostol use according to the MIFEPREX product label.

Gestational age was assessed prior to study enrollment using the date of the woman's last menstrual period, clinical evaluation, and/or ultrasound examination.

About 85% of patients report at least one adverse reaction following administration of MIFEPREX and misoprostol, and many can be expected to report more than one such reaction. The most commonly reported adverse reactions ( > 15%) were nausea, weakness, fever/chills, vomiting, headache, diarrhea, and dizziness (see Table 1). The frequency of adverse reactions varies between studies and may be dependent on many factors including the patient population and gestational age.

Abdominal pain/cramping is expected in all medical abortion patients and its incidence is not reported in clinical studies. Treatment with MIFEPREX and misoprostol is designed to induce uterine bleeding and cramping to cause termination of an intrauterine pregnancy. Uterine bleeding and cramping are expected consequences of the action of MIFEPREX and misoprostol as used in the treatment procedure. Most women can expect bleeding more heavily than they do during a heavy menstrual period [see WARNINGS AND PRECAUTIONS].

Table 1 lists the adverse reactions reported in U.S. clinical studies with incidence > 15% of women.

Table 1 : Adverse Reactions Reported in Women Following Administration of Mifepristone (oral) and Misoprostol (buccal) in U.S. Clinical Studies

Adverse Reaction # US studies Number of Evaluable Women Range of frequency (%) Upper Gestational Age of Studies Reporting Outcome
Nausea 3 1,248 51-75% 70 days
Weakness 2 630 55-58% 63 days
Fever/chills 1 414 48% 63 days
Vomiting 3 1,248 37-48% 70 days
Headache 2 630 41-44% 63 days
Diarrhea 3 1,248 18-43% 70 days
Dizziness 2 630 39-41% 63 days

One study provided gestational-age stratified adverse reaction rates for women who were 57-63 and 64-70 days; there was little difference in frequency of the reported common adverse reactions by gestational age.

Information on serious adverse reactions was reported in six U.S. and four non-U.S. clinical studies, totaling 30,966 women through 70 days gestation who used mifepristone 200 mg orally followed 24-48 hours later by misoprostol 800 mcg buccally. Serious adverse reaction rates were similar between U.S. and non-U.S. studies, so rates from both U.S. and non-U.S. studies are presented. In the U.S. studies, one studied women through 56 days gestation, four through 63 days gestation, and one through 70 days gestation, while in the non-U.S. studies, two studied women through 63 days gestation, and two through 70 days gestation. Serious adverse reactions were reported in < 0.5% of women. Information from the U.S. and non-U.S. studies is presented in Table 2.

Table 2 : Serious Adverse Reactions Reported in Women Following Administration of Mifepristone (oral) and Misoprostol (buccal) in U.S. and Non-US Clinical Studies

Adverse Reaction US Non-US
# of studies Number of Evaluable Women Range of frequency (%) # of studies Number of Evaluable Women Range of frequency (%)
Transfusion 4 17,774 0.03-0.5% 3 12,134 0-0.1%
Sepsis 1 629 0.2% 1 11,155 < 0.01%*
ER visit 2 1,043 2.9-4.6% 1 95 0
Hospitalization Related to Medical Abortion 3 14,339 0.04-0.6% 3 1,286 0-0.7%
Infection without sepsis 1 216 0 1 11,155 0.2%
Hemorrhage NR NR NR 1 11,155 0.1%
NR= Not reported
* This outcome represents a single patient who experienced death related to sepsis.

Postmarketing Experience

The following adverse reactions have been identified during postapproval 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.

Infections and infestations: post-abortal infection (including endometritis, endomyometritis, parametritis, pelvic infection, pelvic inflammatory disease, salpingitis)

Blood and the lymphatic system disorders: anemia Immune system disorders: allergic reaction (including anaphylaxis, angioedema, hives, rash, itching)

Psychiatric disorders: anxiety Cardiac disorders: tachycardia (including racing pulse, heart palpitations, heart pounding) Vascular disorders: syncope, fainting, loss of consciousness, hypotension (including orthostatic), light-headedness

Respiratory, thoracic and mediastinal disorders: shortness of breath

Gastrointestinal disorders: dyspepsia

Musculoskeletal, connective tissue and bone disorders: back pain, leg pain

Reproductive system and breast disorders: uterine rupture, ruptured ectopic pregnancy, hematometra, leukorrhea

General disorders and administration site conditions: pain

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.

Women's Health

Find out what women really need.