Tazemetostat is used to treat epithelioid sarcoma (a rare, slow-growing soft tissue cancer) in adults and children 16 years of age and older that has spread to nearby tissues or to other parts of the body and cannot be treated successfully with surgery. It is also used to treat certain types of follicular lymphoma (FL; a type of cancer that begins in the white blood cells) in adults whose cancer that has returned or did not respond to at least two other medications. Tazemetostat is also used to treat follicular lymphoma in adults that has returned or did not respond to treatment when no other treatment options are available. Tazemetostat is in a class of medications called EZH2 inhibitors. It helps to stop the spread of cancer cells.

Tazemetostat comes as a tablet to take by mouth. It is usually taken twice a day with or without food. Take tazemetostat at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take tazemetostat exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the tablets whole; do not split, chew, or crush them.

If you vomit soon after taking tazemetostat, do not take another dose. Continue your regular dosing schedule.

Your doctor may temporarily or permanently stop your treatment or decrease your dose of tazemetostat depending on the side effects that you experience. Be sure to talk to your doctor about how you are feeling during your treatment. Do not stop taking tazemetostat without talking to your doctor.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Before taking tazemetostat,

• tell your doctor and pharmacist if you are allergic to tazemetostat, any other medications, or any of the ingredients in tazemetostat tablets. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, and nutritional supplements you are taking or plan to take. Be sure to mention any of the following: aprepitant (Emend), carbamazepine (Carbatrol, Teril, others), clarithromycin (Biaxin, in Prevpac), diltiazem (Cardizem, Cartia, Diltzac, others), efavirenz (Sustiva, in Atripla), erythromycin (E.E.S, PCE, others), hormonal contraceptives (birth control pills, patches, rings, or injections), indinavir (Crixivan), itraconazole (Onmel, Sporanox), ketoconazole, modafinil (Provigil), nefazodone, nelfinavir (Viracept), nevirapine (Viramune), phenobarbital, phenytoin (Dilantin, Phenytek), rifabutin (Mycobutin), rifampin (Rifadin, Rimactane, in Rifamate), ritonavir (Norvir, in Kaletra), saquinavir (Fortovase, Invirase), or verapmil (Calan, Covera, Verelan). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with tazemetostat, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
• tell your doctor what herbal products you are taking, especially St. John’s wort.
• tell your doctor if you have or have ever had liver disease.
• tell your doctor if you are pregnant, plan to become pregnant, or plan to father a child. Tazemetostat may interfere with the action of hormonal contraceptives (birth control pills, patches, rings, implants, or injections), so you should not use these as your only method of birth control during your treatment. If you are female, you will have to take a pregnancy test before starting treatment and use a non-hormonal birth control (device that blocks sperm from entering the uterus such as a condom) to prevent pregnancy during your treatment and for 6 months after your final dose. If you are male, you and your female partner should use effective birth control during your treatment and for 3 months after your final dose. Ask your doctor to help you choose a method of birth control that will work for you or your partner. If you or your partner become pregnant while taking tazemetostat, call your doctor immediately. Tazemetostat may harm the fetus.
• tell your doctor if you are breastfeeding. You should not breastfeed during your treatment and for 1 week after your final dose.

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

Skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Tazemetostat may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• loss of appetite
• nausea
• vomiting
• constipation
• diarrhea
• stomach pain
• weight loss
• cough
• headache
• tiredness
• muscle, bone, or joint pain

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or get emergency medical treatment:

• fatigue, easy bruising, fever, bone pain, or pale skin
• unusual bleeding
• skin infection
• shortness of breath

Tazemetostat may cause an increased risk of developing cancer. Talk to your doctor about the risks of taking this medication.

Tazemetostat may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

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).

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.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can’t be awakened, immediately call emergency services at 911.

Keep all appointments with your doctor and the laboratory. For some conditions, your doctor will order a lab test before you begin your treatment to see whether your cancer can be treated with tazemetostat. Your doctor may also order certain lab tests to check your body’s response to tazemetostat.

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.

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