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Generic name: osilodrostatO-sil-OH-droe-stat ]
Drug class: Adrenal corticosteroid inhibitors

Medically reviewed by Judith Stewart, BPharm. Last updated on May 30, 2023.

What is Isturisa?

Isturisa is a cortisol synthesis inhibitor.

Isturisa is used in adults to treat Cushing's disease that cannot be treated with pituitary surgery.

Isturisa is also used in patients who have had pituitary surgery, but the surgery did not cure their Cushing’s disease.


Isturisa can cause serious side effects, such as heartbeat problems or decreased adrenal gland hormones. Call your doctor at once if you have irregular heartbeats, stomach pain, vomiting, loss of appetite, tiredness, or feeling light-headed.

Tell your healthcare provider if you take medicines used to treat certain heart problems.

Before taking this medicine

To make sure Isturisa is safe for you, tell your doctor if you have ever had:

Tell your doctor if you are pregnant or plan to become pregnant. It is not known whether osilodrostat will harm an unborn baby. However, having Cushing's disease during pregnancy may cause complications such as diabetes or eclampsia (dangerously high blood pressure that can lead to medical problems in both mother and baby). The benefit of treating Cushing's disease may outweigh any risks to the baby.

Do not breastfeed while using Isturisa, and for at least 1 week after your last dose.

Isturisa is not approved for use by anyone younger than 18 years old.

How should I take Isturisa?

Take Isturisa exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

You may take Isturisa with or without food.

Your doctor will check your heart function using an electrocardiograph or ECG (sometimes called an EKG). Your next dose may be delayed based on the results of your ECG or other medical tests.

Do not change your dose or dosing schedule without your doctor's advice.

Store Isturisa tablets at room temperature away from moisture and heat.

Dosing information

Usual Adult Dose of Isturisa for Cushing's Syndrome:

INITIAL DOSE: 2 mg orally 2 times a day
TITRATION: Initially, titrate the dose by 1 to 2 mg 2 times a day, no more frequently than every 2 weeks based on the rate of cortisol changes, individual tolerability and patient improvement. If a patient tolerates 10 mg 2 times a day and continues to have elevated 24-hour urine free cortisol (UFC) levels above upper normal limit, the dose can be titrated further by 5 mg 2 times a day every 2 weeks. Monitor cortisol levels from at least two 24-hour urine free cortisol collections every 1 to 2 weeks until adequate response is maintained.
MAINTENANCE DOSE: Should be individualized and determined by titration based on cortisol levels and patient's symptoms. Maintenance dose varies between 2 and 7 mg 2 times a day.
Maximum maintenance dose: 30 mg orally 2 times a day; when maintenance dose is achieved, monitor cortisol levels at least every 1 to 2 months or as indicated.

Use: For the treatment of adult patients with Cushing's disease for whom pituitary surgery is not an option or has not been curative

What happens if I miss a dose?

Skip the missed dose and use your next dose at the regular time. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include nausea, vomiting, stomach pain, extreme tiredness, feeling light-headed, or fainting.

What to avoid

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Isturisa side effects

Get emergency medical help if you have signs of an allergic reaction to Isturisa: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

Common Isturisa side effects may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Isturisa?

Isturisa can cause a serious heart problem. Your risk may be higher if you also use certain other medicines for infections, asthma, heart problems, high blood pressure, depression, mental illness, cancer, malaria, or HIV.

Other drugs may interact with osilodrostat, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Isturisa only for the indication prescribed.

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