Pexidartinib is used in adults to treat giant cell tumor of the tendon sheath (also called tenosynovial giant cell tumor, or pigmented villonodular synovitis) not likely to improve with surgery.

Pexidartinib is available only from a certified pharmacy under a special program. You must be registered in the program and understand the risks and benefits of pexidartinib.

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

Pexidartinib can harm your liver. You will need frequent blood tests to check your liver function before and during treatment with pexidartinib.

Stop using pexidartinib and call your doctor at once if you have dark urine or jaundice (yellowing of the skin or eyes).

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.

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

Pexidartinib 125 mg capsules are usually taken twice per day with a low-fat meal (about 11 to 14 grams of fat).

Pexidartinib 200 mg capsules are usually taken twice a day on an empty stomach, at least 1 hour before or 2 hours after a meal or snack.

Swallow the capsule whole and do not crush, chew, break, or open it.

If you vomit shortly after taking pexidartinib, do not take another dose. Take your next dose as scheduled.

You will need blood tests to check your liver function before and during treatment with pexidartinib.

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

Store at room temperature away from moisture and heat. Keep the tablets in their original container, along with the packet or canister of moisture-absorbing preservative.

Usual Adult Dose for Giant Cell Tumor of Bone:

400 mg orally 2 times a day

Use: For symptomatic (TGCT) associated with severe morbidity or functional limitations and not amenable to improvement with surgery

Tell your doctor if you have or have ever had:

• liver or kidney disease.

Pexidartinib can harm an unborn baby if the mother or the father is using this medicine.

• If you are a woman, you may need a pregnancy test to make sure you are not pregnant. Use birth control while using this medicine and for at least 1 month after your last dose.

• If you are a man, use 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.

Pregnancy may be less likely to occur while the mother or the father is using this medicine. Both men and women should still use birth control to prevent pregnancy because the medicine can harm an unborn baby.

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

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

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

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Do not remove the desiccant (small packet included with medication to absorb moisture) from the bottle, if one has been provided.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

Do not eat grapefruit or drink grapefruit juice while taking this medication.

Grapefruit may interact with pexidartinib and cause side effects. Avoid consuming grapefruit products.

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

Stop using pexidartinib and call your doctor at once if you have dark urine or jaundice (yellowing of the skin or eyes).

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

• right-sided upper stomach pain;

• loss of appetite, nausea, vomiting;

• rash;

• fever, tiredness; or

• itching.

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

Common side effects of pexidartinib may include:

• abnormal lab results;

• tiredness;

• puffy eyes;

• changes in the color of your hair;

• rash, itching, hives, skin redness, acne; 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.

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

This list is not complete and many other drugs may affect pexidartinib. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.