Key takeaways
- Mifepristone is a generic drug that is available as an oral tablet. It’s typically taken once per day with a meal.
- For Cushing syndrome, mifepristone works by blocking cortisol receptors, which helps lower cortisol activity. This can help lower blood sugar levels.
- A few examples of more common side effects of mifepristone when used for Cushing syndrome include nausea or vomiting, fatigue (low energy), and headache.
Mifepristone is a generic drug that is used to help manage high blood sugar levels in people with Cushing syndrome. Specifically, it can be used in adults who have type 2 diabetes or prediabetes, and surgery to treat Cushing syndrome has not worked or is not an option.
Mifepristone has a boxed warning. For details, see “Boxed warning: Risk of loss of pregnancy” in the “Things to consider for mifepristone” section.
Mifepristone has other uses that may come with different risks. If you have questions about other uses or risks of mifepristone, talk with your doctor or pharmacist.
Mifepristone is part of a drug class called cortisol receptor blocker. It works to lower cortisol activity by blocking cortisol receptors.
By blocking the effects of excess cortisol, it stops cortisol from signaling the body to release more sugar, which is the cause of high blood sugar levels in Cushing syndrome
Key term
Cushing syndrome is a rare hormone condition that results from long-term high cortisol levels. Cortisol, commonly known as the stress hormone, regulates the level of sugar in your blood. High cortisol levels can cause your blood sugar to rise, which can lead to prediabetes and type 2 diabetes.
Read more: What to know about Cushing syndrome.
Does mifepristone decrease cortisol?
No, mifepristone does not lower cortisol levels. Instead, it blocks the effects of high cortisol.
Mifepristone is available as an oral tablet and comes in one strength: 300 milligrams (mg).
The recommended starting dosage of mifepristone is 300 mg once per day, taken with a meal. Your doctor may increase your daily dose by 300 mg every 2 to 4 weeks if needed. For most people, the maximum dose is 1,200 mg per day.
If you have kidney or liver problems, your doctor may recommend a different dose of mifepristone.
Some of the more common side effects reported with mifepristone when used for managing high blood sugar in people with Cushing syndrome include:
- nausea or vomiting
- fatigue (low energy)
- headache
- joint pain
- swelling of the legs, feet, and hands
- dizziness
- decreased appetite
For some people, mifepristone can cause allergic reaction. But, this side effect wasn’t reported in the drug’s studies. If you experience an allergic reaction with mifepristone, talk with your doctor. If your symptoms are serious or life-threatening, such as difficulty breathing, call 911 or your local emergency number right away.
This is not a full list of mifepristone’s side effects. For more information about side effects, talk with your doctor or pharmacist or check out the drug’s prescribing information.
Read more: Details on mifepristone’s more common and serious side effects.
The following is important information to consider and discuss with your doctor or pharmacist before taking mifepristone.
Interactions
The following is a list of medications and foods that can interact with mifepristone. This list does not contain all drugs that may interact with the drug. Talk with your doctor about all the medications, supplements, vitamins, and herbs you are taking to make sure it is safe for you to take mifepristone.
- drugs that get broken down by CYP3A (an enzyme), such as simvastatin (Zocor) and cyclosporine
- drugs that decrease the action of CYP3A, such as ketoconazole and clarithromycin
- drugs that increase the action of CYP3A, such as phenytoin (Dilantin), carbamazepine, and St. John’s wort
- drugs that get broken down by other enzymes, such as warfarin (Jantoven), fluvastatin, and nonsteroidal anti-inflammatory drugs
- hormones in birth control, such as birth control pills
Boxed warning: Risk of loss of pregnancy
When used for managing high blood sugar in people with Cushing syndrome, mifepristone has a boxed warning about the risk of loss of pregnancy. A boxed warning is the most serious warning from the Food and Drug Administration (FDA) about drug effects that may be dangerous.
Mifepristone blocks the effects of the hormone progesterone, which prepares the uterus for pregnancy. Because of this effect, mifepristone will cause pregnancy loss.
Due to this risk, mifepristone should not be used in pregnant people or those planning a pregnancy. Before starting treatment with the drug, your doctor will have you take a pregnancy test to ensure you’re not pregnant.
Breastfeeding
It’s not known whether mifepristone should be taken while breastfeeding, but mifepristone is present in breastmilk. The effects of long-term mifepristone use on breastfeeding or in a breastfed child are not known.
You and your doctor can weigh the health benefits of breastfeeding with mifepristone and potential side effects on a child who is breastfed.
Other warnings
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:
- long-term treatment with corticosteroids
- health conditions or medications that increase the risk of bleeding
- endometrial hyperplasia or endometrial cancer
- unexplained vaginal bleeding in people with a uterus
- low potassium levels
- previous allergic reaction to this or a similar drug
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.
Whether you have health insurance or not, cost may be a factor when you’re considering mifepristone. What you’ll pay for mifepristone for Cushing syndrome may depend on several things, such as your treatment plan and the pharmacy you use.
Mifepristone is a generic drug that is used to help manage high blood sugar in certain people with Cushing syndrome. If you have questions about whether mifepristone is right for you, talk with your doctor.
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.