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Mifepristone Side Effects

For the Consumer

Applies to mifepristone: oral tablet

Along with its needed effects, mifepristone 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 immediately if any of the following side effects occur while taking mifepristone:

Less common 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 the arms, jaw, back, or neck
  • painful or difficult urination
  • pale, cold, or clammy skin
  • shortness of breath
  • sudden increase in stomach or shoulder pain
  • sweating
  • unusual or large amount of vaginal bleeding

Some side effects of mifepristone may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common Less common
  • Acid or sour stomach
  • anxiety
  • belching
  • cough
  • fainting or lightheadedness 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 the eyes and cheekbones
  • pale skin
  • shaking chills
  • stomach discomfort, upset, or pain
  • stuffy or runny nose
  • tightness of the chest
  • trouble sleeping
  • troubled breathing
  • troubled breathing, exertional
  • unusual bleeding or bruising

For Healthcare Professionals

Applies to mifepristone: oral tablet


The most commonly reported adverse reactions were nausea, weakness, fever/chills, vomiting, headache, diarrhea, and dizziness.[Ref]


Very common (10% or more): Hypertension (24%)
Uncommon (0.1% to 1%): Hypotension (0.25%), hot flush
Rare (less than 0.1%): Myocardial infarction, induced Adam-Stokes syndrome, superficial thrombophlebitis
Postmarketing reports: Syncope, fainting, loss of consciousness, hypotension (including orthostatic), light-headedness, tachycardia (including racing pulse, heart palpitations, heart pounding)[Ref]


Very common (10% or more): Thyroid function test abnormal (18%) in patients with Cushing syndrome[Ref]

It was reported that of the 42 Cushing syndrome patients with detectable TSH at baseline, eight (19%) had increases in TSH above the normal range, while remaining asymptomatic. The TSH levels returned to normal in most patients when this drug was discontinued at the end of the study.
Adrenal insufficiency was reported in two subjects (4%) in Study 400. The most typical symptoms of adrenal insufficiency were nausea and decreased appetite. Adrenal insufficiency resolved in both cases with interruption of this drug and/or dexamethasone administration.[Ref]


Very common (10% or more): Nausea (48%), vomiting (26%), dry mouth (18%), diarrhea (12%), constipation (10%), gastric discomfort, abdominal pain
Common (1% to 10%): Light or moderate cramping
Rare (less than 0.1%): Gastric bleeding, necrotising pancreatitis
Postmarketing reports: Dyspepsia, gastroesophageal reflux[Ref]


Heavy bleeding occurs in about 5% of the cases and may require hemostatic curettage in up to 1.4% of the cases.
In clinical trials surgical evacuation was needed in 10% to 12% of women, with some studies reporting a rate as high as 20% to 30%. Bleeding can be prolonged for several days after prostaglandin analog administration and sometimes leads to a decrease in hemoglobin levels.[Ref]

Very common (10% or more): Uterine contractions or cramping (up to 45%) following prostaglandin intake, endometrial hypertrophy (38%), vaginal bleeding, uterine spasm
Common (1% to 10%): Endometritis, pelvic inflammatory disease, heavy uterine bleeding, prolonged post abortion bleeding, spotting, severe hemorrhage, breast tenderness
Uncommon (0.1% to 1%): Uterine rupture after prostaglandin intake (during induction of second trimester termination of pregnancy or labor induction for fetal death in utero during the third trimester), hemorrhagic shock, salpingitis
Rare (less than 0.1%): Hydatiform mole, ectopic pregnancy, amniotic band syndrome, gestational trophoblastic tumor, uteroplacental apoplexy, bilateral adnexal mass, intrauterine adhesion, ovarian cyst rupture, breast abscess, hematosalpinx, uterine rupture
Postmarketing reports: Post-abortal infection (including endometritis, endomyometritis, parametritis, pelvic infection, pelvic inflammatory disease, salpingitis); hematometra, leukorrhea, vaginal hemorrhage, metrorrhagia[Ref]


Very common (10% or more): Blood potassium decreased (34%) in Cushing syndrome patients
Rare (less than 0.1%): Thrombotic thrombocytopenic purpura, thrombocytopenia, induced systemic lupus erythematosus
Postmarketing reports: Anemia[Ref]


In Cushing syndrome patients:
Very common (10% or more): Decreased appetite (20%), anorexia (10%)
Postmarketing reports: Increased triglycerides, hypoglycemia[Ref]


Very common (10% or more): Arthralgia (30%), back pain (16%), myalgia (14%), pain in the extremity (12%)
Rare (less than 0.1%): Limb spasm
Postmarketing reports: Muscular weakness, flank pain, musculoskeletal chest pain[Ref]

Nervous system

Very common (10% or more): Headache (44%), dizziness (22%), somnolence (10%)
Rare (less than 0.1%): Vagal symptoms (hot flushes, dizziness, chills), epilepsy, neurogenic tinnitus[Ref]


Very common (10% or more): Fatigue (48%), peripheral edema (26%), pain (14%), chill, fever
Common (1% to 10%): Fainting
Rare (0.01% to 0.1%): Malaise
Very rare (less than 0.01%): Fatal toxic shock caused by Clostridium sordellii endometritis or Escherichia coli (use of mifepristone followed by non authorized vaginal administration of misoprostol oral tablets)
Postmarketing reports: Asthenia, edema, pitting edema, thirst[Ref]


Very common (10% or more): Anxiety (10%)
Rare (less than 0.1%): Mania
Postmarketing reports: Insomnia[Ref]


Very common (10% or more): Dyspnea (16%), sinusitis (14%), nasopharyngitis (12%)
Rare (less than 0.1%): Bronchospasm, induced bronchial asthma
Frequency not reported: Shortness of breath[Ref]


Uncommon (0.1% to 1%): Skin rashes (0.2%), pruritus
Rare (0.01% to 0.1%): Urticaria, erythroderma, erythema nodosum, toxic epidermal necrolysis
Very rare (less than 0.01%): Angioedema[Ref]


Rare (less than 0.1%): Abnormal liver function tests, hepatic failure, hepatorenal failure[Ref]


Rare (less than 0.1%): Anaphylaxis
Postmarketing reports: Allergic reaction (including anaphylaxis, angioedema, hives, rash, itching)[Ref]


Rare (less than 0.1%): Ophthalmoplegia, periorbital edema[Ref]


Rare (less than 0.1%): Elevated alpha-feto protein, elevated carcinoembryonic antigen[Ref]


Rare (less than 0.1%): Renal failure[Ref]


1. "Product Information. Mifeprex (mifepristone)" Danco Laboratories, New York, NY.

2. "Product Information. Korlym (mifepristone)." Corcept Therapeutics Incorporated, Menlo Park, CA.

3. Cerner Multum, Inc. "Australian Product Information." O 0

4. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

Some side effects of mifepristone may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.