Fedratinib may cause encephalopathy (a serious and potentially fatal disorder of the nervous system), including Wernicke’s encephalopathy (a type of encephalopathy caused by a lack of thiamine [vitamin B1]). Tell your doctor if you have or have ever had a thiamine deficiency. If you experience any of the following symptoms, stop taking fedratinib and call your doctor immediately or get emergency medical treatment: difficulty moving or keeping your balance, weakness of the legs or arms that keeps getting worse, confusion, drowsiness, difficulty understanding or speaking, loss of memory, vision problems (including double vision and abnormal eye movements), or changes in personality.

Your doctor may prescribe medications to reduce the risk of side effects you may have from taking fedratinib. Tell your doctor right away if you have nausea, vomiting, diarrhea, or weight loss that does not get better with treatment.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain tests to check your body’s response to fedratinib.

Your doctor or pharmacist will give you the manufacturer’s patient information sheet (Medication Guide) when you begin treatment with fedratinib and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website (http://www.fda.gov/Drugs/DrugSafety/ucm085729.htm) or the manufacturer’s website to obtain the Medication Guide.

Fedratinib is used to treat adults with certain types of myelofibrosis (MF; a cancer of the bone marrow in which the bone marrow is replaced by scar tissue and causes decreased blood cell production). Fedratinib is in a class of medications called kinase inhibitors. It works by blocking the action of the abnormal protein that signals cancer cells to multiply. This helps stop or slow the spread of cancer cells.

Fedratinib comes as a capsule to take by mouth. It is usually taken once a day, with or without food. Taking fedratinib with a high fat meal may help to reduce nausea and vomiting. Take fedratinib at around the same time 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 fedratinib exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Your doctor will order blood tests before and during your treatment to see how you are affected by this medication. Your doctor may increase or decrease your dose of fedratinib during your treatment, or may tell you to stop taking fedratinib temporarily or permanently. This depends on how well the medication works for you, your lab test results, and if you experience side effects. Talk to your doctor about how you are feeling during your treatment.

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

Before taking fedratinib,

• tell your doctor and pharmacist if you are allergic to fedratinib, any other medications, or any of the ingredients in fedratinib capsules. 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, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: clarithromycin (Biaxin, in PrevPac), diltiazem (Cardizem, Dilacor, Tiazac, others), erythromycin (E.E.S., E-mycin, Erythrocin), idelalisib (Zydelig), indinavir (Crixivan), itraconazole (Sporanox), ketoconazole (Nizoral), metoprolol (Lopressor, Toprol XL, in Dutoprol, others), midazolam (Versed), nefazodone, nelfinavir (Viracept), omeprazole (Prilosec, in Zegerid), pantoprazole (Protonix), ribociclib (Kisqali, Kisqali, in Femera), ritonavir (Norvir), ruxolitinib (Jakafi), and saquinavir (Invirase). 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 fedratinib, 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 if you if you smoke or if you have ever smoked. Also tell your doctor if you have or have ever had cancer, pancreatitis (swelling of the pancreas), blood clots, a stroke, a heart attack or other heart problems, liver or kidney disease.
• tell your doctor if you are pregnant or plan to become pregnant. If you become pregnant while taking fedratinib, call your doctor.
• do not breastfeed during your treatment with fedratinib and for at least 1 month after your final dose.
• if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking fedratinib.

Talk to your doctor about eating grapefruit and drinking 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.

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

• nausea
• vomiting
• diarrhea
• constipation
• tiredness
• muscle spasms
• arm, leg, or bone pain
• headache
• weight gain
• dizziness

Some side effects can be serious. If you experience any of these symptoms or those listed in the IMPORTANT WARNING section, call your doctor immediately or get emergency medical treatment:

• unusual bleeding or bruising
• fever, chills, cough, painful or frequent urination, or other signs of infection
• nausea, extreme tiredness, unusual bruising or bleeding, lack of energy, loss of appetite, pain in the upper right part of the stomach, yellowing of the skin or eyes, or flu-like symptoms
• shortness of breath, fast heartbeat, headache, dizziness, pale skin, confusion, or tiredness
• pain in the chest, arms, back, neck, jaw, or stomach; breaking out in cold sweat; lightheadedness
• slow or difficult speech; sudden weakness or numbness of the face, arm or leg; sudden headache; sudden vision problems; sudden difficulty walking
• swelling, pain, tenderness, warmth or redness in one or both legs
• shortness of breath, coughing up blood, fast heartbeat, fast breathing, pain when breathing deeply

Fedratinib may increase your risk of developing other cancers, such as lymphoma (cancer that begins in the cells that fight infection). Talk to your doctor about the risks of receiving this medication.

Fedratinib 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.

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.

• Inrebic^®