Key takeaways

  • Mifepristone can be used for a a few different conditions. More common side effects and risks associated with the drug vary depending on the condition being treated.
  • A few more common side effects seen with mifepristone when treating either condition include nausea or vomiting, headache, and dizziness.
  • Mifepristone may be used with misoprostol when used for a medical abortion. Side effects of these drugs together are similar to those seen with mifepristone alone.

Side effects of mifepristone may vary depending on the condition the drug is being used to treat. Learn about the common and serious side effects mifepristone can cause and tips for managing some of those side effects.

Mifepristone has boxed warnings. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). For details, see “Boxed warnings” in the “Serious side effects of mifepristone” section.

More common side effects reported in people taking mifepristone for medical abortion include:

  • nausea or vomiting
  • weakness
  • fever or chills
  • headache
  • diarrhea
  • dizziness

More common side effects reported in people taking mifepristone for managing high blood sugar in people with Cushing syndrome include:

In most cases, these side effects should be temporary, and some may be easily managed. But if you have symptoms that are ongoing or bothersome, talk with your doctor or pharmacist. Do not stop taking mifepristone unless your doctor recommends it.

Medical Perspective

“To help with nausea or vomiting, start with simple steps like avoiding strong smells or foods that upset your stomach, eating small meals more often, and sipping fluids to stay hydrated. Ginger and vitamin B6 may also help, and relaxation techniques can be useful for some people.”

— Andrew Perugini, PharmD

Learn about the best foods to eat when you are feeling nauseous.

Quotes represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

Mifepristone may cause serious side effects, such as:

If you develop serious side effects while taking mifepristone, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Note: It is possible for mifepristone to cause an allergic reaction. But, this side effects wasn’t reported in the drug’s studies.

The following lists may not include all possible side effects of the drug. For more information, you can refer to mifepristone’s prescribing information when used for medical abortion and high blood sugar related to Cushing syndrome.

Boxed warnings

Mifepristone has boxed warnings. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

Risk of loss of pregnancy

When mifepristone is used to help manage high blood sugar in people with Cushing syndrome, it has a boxed warning for the risk of loss of pregnancy. Because of this risk, for people who can become pregnant your doctor will order a pregnancy test before starting you on treatment with mifepristone.

Risks of serious infections and serious bleeding

When mifepristone is used for medical termination of pregnancy, it has boxed warnings for the risk of serious infection and serious bleeding.

  • Mifepristone may cause a serious bacterial infection, including fatal septic shock in rare cases. Your doctor will monitor you for symptoms of infection during your treatment with mifepristone.
  • Bleeding may occur with mifepristone. But, prolonged heavy bleeding may be serious and a sign of incomplete abortion or other complications that require immediate medical attention.

For this use, mifepristone is offered through a REMS program which means it has to be prescribed by a certified healthcare professional.

Mifepristone may be taken with misoprostol for a medical abortion.

When these drugs are taken together, you may first experience strong abdominal cramping and heavy bleeding. Light cramping may continue for several days, and light bleeding often continues for several weeks. Some people may also experience nausea or vomiting, diarrhea, and fever after taking these two medications.

Before taking mifepristone, discuss your health history with your doctor. Mifepristone may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

  • ectopic pregnancy
  • chronic adrenal failure
  • long-term treatment with corticosteroids
  • history of bleeding disorders
  • inherited porphyrias
  • intrauterine device (IUD)
  • history of unexplained vaginal bleeding
  • taking certain other medications that may interact with mifepristone, such as simvastatin (Zocor) or cyclosporine
  • heart failure and coronary vascular disease
  • previous allergic reaction to this or a similar drug
  • pregnancy
  • breastfeeding

Experiencing side effects? After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking this drug and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.

Like most drug, mifepristone can cause side effects. If you have questions or concerns about side effects with mifepristone, talk with your doctor or pharmacist for more information.

Disclaimer: While Healthline strives for factual, comprehensive, and current information, this article is not a substitute for a licensed healthcare professional’s expertise. Always consult a doctor before taking or discontinuing any medication. Drug information is subject to change and may not cover all uses, directions, precautions, warnings, interactions, reactions, or adverse effects. The lack of a warning does not guarantee a drug’s safety, effectiveness, or appropriateness for all patients or specific uses. Learn more about our approach to content integrity.