Mifeprex Side Effects

Generic name: mifepristone

Medically reviewed by Drugs.com. Last updated on Jan 14, 2024.

Note: This document contains side effect information about mifepristone. Some dosage forms listed on this page may not apply to the brand name Mifeprex.

Applies to mifepristone: oral tablet.

Serious side effects of Mifeprex

Along with its needed effects, mifepristone (the active ingredient contained in Mifeprex) 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

• Excessively heavy vaginal bleeding
• unusual tiredness or weakness

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

Other side effects of Mifeprex

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

• Abdominal or stomach pain or uterine cramping
• back pain
• diarrhea
• dizziness
• headache
• nausea or vomiting

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.

General

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

Cardiovascular

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]

Endocrine

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): Thyroid function test abnormal (18%) in patients with Cushing syndrome^[Ref]

Gastrointestinal

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]

Genitourinary

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]

Hematologic

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]

Metabolic

In Cushing syndrome patients:

Very common (10% or more): Decreased appetite (20%), anorexia (10%)

Postmarketing reports: Increased triglycerides, hypoglycemia^[Ref]

Musculoskeletal

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]

Other

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 (the active ingredient contained in Mifeprex) followed by non authorized vaginal administration of misoprostol oral tablets)

Postmarketing reports: Asthenia, edema, pitting edema, thirst^[Ref]

Psychiatric

Very common (10% or more): Anxiety (10%)

Rare (less than 0.1%): Mania

Postmarketing reports: Insomnia^[Ref]

Respiratory

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]

Dermatologic

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]

Hepatic

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

Hypersensitivity

Rare (less than 0.1%): Anaphylaxis

Postmarketing reports: Allergic reaction (including anaphylaxis, angioedema, hives, rash, itching)^[Ref]

Ocular

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

Oncologic

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

Renal

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

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

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