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Overview: Isturisa is used to treat Cushing’s disease, a disorder where you have too much cortisol (a stress hormone) in your body. It works by reducing the amount of cortisol your body makes. Common side effects include tiredness, nausea, headache, and fluid retention. Serious side effects include reduced adrenal function, heart rhythm changes, and hormonal imbalance. Contact your health care provider if you notice your legs swelling, breathing problems, or feel like your heart is beating fast or skipping beats.

Uses

What is Isturisa used for?

Isturisa (osilodrostat) is commonly used to treat Cushing’s disease.

Isturisa may also be used for other conditions as determined by your health care provider.

How does Isturisa work (mechanism of action)?

Cortisol is a stress hormone that affects various body functions, including inflammation, blood pressure, and blood sugar management. Cushing’s disease is a disorder where your adrenal glands make too much cortisol. Isturisa reduces the amount of cortisol your body makes. 

How is Isturisa supplied (dosage forms)?

Brands and other names

  • Isturisa

Dosage forms and strengths

  • 1 mg, 5 mg, 10 mg oral tablets

How should I store Isturisa?

Isturisa should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when transporting it. Protect Isturisa moisture.

Side Effects

What are the most common side effects of Isturisa?

The most common side effects of Isturisa are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Reduced adrenal function (see below)
  • Tiredness
  • Nausea
  • Headache
  • Fluid retention

There may be other side effects of Isturisa that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of Isturisa?

While less common, the most serious side effects of Isturisa are described below, along with what to do if they happen.

Severe Allergic Reactions. Isturisa may cause allergic reactions, which can be serious. Stop taking Isturisa and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Reduced Adrenal Function. Isturisa can cause an excessive decrease in the amount of cortisol your adrenal glands produce (adrenal insufficiency). Sometimes the reduction in adrenal function can be life-threatening. Tell your health care provider if you have any of the following symptoms of adrenal insufficiency.

  • Nausea and vomiting
  • Weakness, tiredness, or lack of energy
  • Stomach pain
  • Loss of appetite
  • Low blood pressure
  • Low blood sugar
  • Dizziness

Heart Rhythm Changes. Isturisa may cause a rare, dangerous heart rhythm problem called QT prolongation and torsade de pointes. Some people have a higher risk of this, including people who are older, have other people in their family who have had these conditions, have low potassium or magnesium levels, or who take medicines that can prolong the QT interval. Tell your health care provider right away if you faint or have changes in your heart rate or rhythm, such as a fast or skipping heartbeat.

Hormonal Imbalance. The cortisol-blocking effect of Isturisa may cause unwanted hormonal imbalance, which may affect your electrolytes, water retention, and sexual characteristics. Tell your health care provider if you have any of the following symptoms of hormonal imbalance.

  • High blood pressure
  • Fluid retention, especially in your legs, ankles, or feet
  • Excessive hair growth
  • Acne

Warnings & Precautions

Who should not use Isturisa?

Allergies to Ingredients. People who are allergic to any of the following should not take Isturisa.

  • Isturisa
  • Osilodrostat
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific Isturisa products they stock.

What should I know about Isturisa before using it?

Do not take Isturisa unless it has been prescribed to you by a health care provider. Take it as prescribed.

Follow any dosing instructions from your health care provider closely. They will tell you exactly how many Isturisa tablets to take. 

Do not share Isturisa with other people, even if they have the same condition as you. It may harm them.

Keep Isturisa out of the reach of children.

While you are taking Isturisa, your health care provider may perform regular blood or urine tests to make sure that Isturisa is both safe and working for you. Keep all appointments you make with your health care provider.

What should I tell my health care provider before using Isturisa?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if Isturisa is right for you.

In particular, make sure that you discuss any of the following.

Other Medicines and Supplements. Isturisa may interact with other medicines and supplements. Before taking Isturisa, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Heart problems, including rhythm or rate problems and heart failure
  • Electrolyte imbalance, such as low potassium or magnesium levels
  • Kidney problems
  • Liver problems

Pregnancy. It is not known if or how Isturisa could affect pregnancy or harm an unborn baby. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. It is not known if Isturisa passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should stop breastfeeding or stop Isturisa.

How can I get more information about Isturisa?

For more information about Isturisa, you can visit the drugmaker’s website at www.isturisa.com or call them at 888-855-7273.

Interactions

Does Isturisa interact with foods or drinks?

There are no known interactions between Isturisa and foods or drinks.

It is unknown if drinking alcohol will affect Isturisa, but the risk of tiredness may be increased if you drink alcohol with Isturisa.

Does Isturisa interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking Isturisa.

  • Carbamazepine (Carbatrol, Tegretol, and others), which is a medicine commonly used to treat seizures or nerve pain
  • Clarithromycin, erythromycin, or moxifloxacin, which is a medicine used for bacterial infections
  • Itraconazole (Sporanox, Tolsura), which is a medicine used for fungal infections
  • Phenobarbital, which is a medicine used for sedation or seizures
  • Rifampin (Rifadin), which is a medicine commonly used to treat an infection called tuberculosis
  • Theophylline (Theo-24, Elixophyllin), which is a medicine for asthma or certain other breathing problems
  • Tizanidine (Zanaflex), which is a muscle relaxant
  • An antipsychotic, which is a medicine for certain mental health conditions
  • A tricyclic antidepressant, such as amitriptyline, nortriptyline, or protriptyline, even if it is not used for depression
  • Medicines that can cause QT prolongation, which is a potentially dangerous heart rhythm problem

Many other medicines may alter the blood levels of Isturisa, and vice versa. Tell your health care provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with Isturisa. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much Isturisa?

If you or someone else has used too much Isturisa, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of Isturisa?

If you miss a dose, take the next dose at the regularly scheduled time. Do not take extra or double doses.

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