pexidartinib

What is the most important information I should know about pexidartinib?

Pexidartinib can cause severe or fatal effects on your liver. You will need frequent blood tests to check your liver function during treatment.

Tell your doctor if you have other symptoms of liver problems, such as loss of appetite, stomach pain (upper right side), nausea, vomiting, tiredness, itching, or fever.

What is pexidartinib?

Pexidartinib is used to treat giant cell tumor of the tendon sheath (also called tenosynovial giant cell tumor, or pigmented villonodular synovitis).

Pexidartinib is available only under a special program. You must be registered in the program and understand the risks and benefits of this medicine.

Pexidartinib may also be used for purposes not listed in this medication guide.

What should I discuss with my healthcare provider before taking pexidartinib?

Tell your doctor if you have ever had:

• liver disease; or
• kidney disease.

• If you are a woman, you may need to have a negative pregnancy test before starting this treatment. Do not use pexidartinib if you are pregnant. Use effective birth control to prevent pregnancy while you are using this medicine and for at least 1 month after your last dose.
• If you are a man, use effective birth control if your sex partner is able to get pregnant. Keep using birth control for at least 1 week after your last dose.
• Tell your doctor right away if a pregnancy occurs while either the mother or the father is using pexidartinib.

This medicine may affect fertility (ability to have children) in both men and women. However, it is important to use birth control to prevent pregnancy because pexidartinib can harm an unborn baby.

How should I take pexidartinib?

You must remain under the care of a doctor while taking pexidartinib.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

If you vomit shortly after taking pexidartinib, do not take another dose. Wait until your next scheduled dose time to take the medicine again.

You will need blood tests to check your liver function before you start taking pexidartinib and every 1 to 3 weeks for the first 2 months. After that your liver function will be checked at least every 3 months as you continue taking this medicine.

Your next dose may be delayed based on the results of your liver function tests.

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?

What should I avoid while taking pexidartinib?

Grapefruit may interact with pexidartinib and lead to unwanted side effects. Avoid the use of grapefruit products.

What are the possible side effects of pexidartinib?

Tell your doctor if you have other symptoms of liver problems, such as:

• right-sided upper stomach pain;
• loss of appetite, nausea, vomiting;
• fever, tiredness; or
• itching.

Your pexidartinib doses may be delayed or permanently discontinued if you have certain side effects.

Common side effects may include:

• abnormal liver function tests;
• high cholesterol;
• low blood cell counts;
• puffy eyes;
• changes in the color of your hair;
• rash; or
• decreased or altered sense of taste.

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 pexidartinib?

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Pexidartinib can harm your liver, especially if you also use certain medicines for infections, tuberculosis, depression, birth control, hormone replacement, high cholesterol, heart problems, high blood pressure, seizures, pain, or arthritis (including Tylenol, Advil, Motrin, or Aleve).

Some medicines should be taken separately from your dose of pexidartinib:

• If you take an antacid, take your pexidartinib dose 2 hours before or 2 hours after you take the antacid.
• If you take medicine for heartburn or stomach acid (such as ranitidine, cimetidine, famotidine, Pepcid, Tagamet, or Zantac), take your pexidartinib dose 2 hours before or 10 hours after you take the antacid.

You may not be able to take a proton pump inhibitor stomach acid reducer such as dexlansoprazole, esomeprazole, lansoprazole, omeprazole, pantoprazole, rabeprazole, Nexium, Prevacid, Prilosec, Protonix, and others.

Many drugs can affect pexidartinib, and some drugs should not be used at the same time. Tell your doctor about all your current medicines and any medicine you start or stop using. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here.

Where can I get more information?

Your pharmacist can provide more information about pexidartinib.