Mifeprex Side Effects

Generic name: mifepristone

Medically reviewed by Drugs.com. Last updated on Feb 25, 2024.

Note: This document provides detailed information about Mifeprex Side Effects associated with mifepristone. Some dosage forms listed on this page may not apply specifically to the brand name Mifeprex.

Applies to mifepristone: oral tablet.

Common 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:

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:

For healthcare professionals

Applies to mifepristone: oral tablet.

General adverse events

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

• 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]

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

• 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]

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]

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

Mifeprex side effects can vary depending on the individual. 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.

Medical Disclaimer