Inrebic is a prescription medicine used to treat myelofibrosis in adults.

Myelofibrosis is a rare type of bone marrow cancer that affects your body's ability to produce blood cells.

It is not known if Inrebic is safe and effective in children.

Some people using Inrebic have developed vitamin B1 deficiency that resulted in serious and sometimes fatal brain damage. Your vitamin B1 levels will need to be checked before and during treatment, and you may need to take a vitamin B1 supplement.

Get emergency medical help if you have symptoms such as drowsiness, confusion, memory problems, vision problems, unusual eye movements, or problems with coordination and muscle movement.

Call your doctor if you are sick with vomiting or diarrhea even while taking medications to prevent these side effects.

Take Inrebic exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

You may take Inrebic with or without food. Take with a high-fat meal if Inrebic upsets your stomach.

Your vitamin B1 (thiamine) levels will need to be checked before and during treatment with Inrebic. You may need to take a vitamin B1 supplement.

You may be given other medications to help prevent nausea, vomiting, and diarrhea. Keep using these medicines for as long as your doctor has prescribed.

Some people using Inrebic have developed vitamin B1 deficiency that resulted in serious and sometimes fatal brain damage. Your vitamin B1 levels will need to be checked before and during treatment with Inrebic. You may need to take a vitamin B1 supplement.

Call your doctor if you are sick with vomiting or diarrhea even while taking medications to prevent these side effects. You can easily become malnourished from vomiting and diarrhea. This can lead to low vitamin B1 levels.

Fedratinib can lower your blood cell counts and affect liver function. Your blood will need to be tested often. Your cancer treatments may be delayed based on the results.

Do not change your dose or stop taking Inrebic without your doctor's advice.

Store at room temperature away from moisture and heat.

Usual Adult Dose for Myelofibrosis:

For patients with a baseline platelet count of 50 x 109/L or greater:
400 mg orally once a day

Management of thiamine levels and Wernicke's encephalopathy (WE):
-Assess thiamine levels and nutritional status prior to starting therapy, periodically during therapy, and as indicated.
-Do not initiate this drug in patients with thiamine deficiency; replete thiamine prior to therapy initiation and during therapy if thiamine levels are low.
-If Wernicke's encephalopathy is suspected, immediately discontinue therapy and initiate parenteral thiamine treatment.
-Monitor until symptoms resolve or improve and thiamine levels normalize.

Use: For the treatment of intermediate-2 or high-risk primary or secondary (post-polycythemia vera or post-essential thrombocythemia) myelofibrosis (MF)

To make sure Inrebic is safe for you, tell your doctor if you have ever had:

• low levels of platelets or red blood cells;

• liver disease;

• kidney disease; or

• if you have been taking ruxolitinib (Jakafi).

It is not known whether fedratinib will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

You should not breastfeed while using Inrebic, and for at least 1 month 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.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

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

Some people using Inrebic have developed vitamin B1 deficiency that resulted in serious and sometimes fatal brain damage. Seek emergency medical attention if you have symptoms such as:

• drowsiness, confusion, memory problems;

• vision problems, unusual eye movements; or

• problems with coordination and muscle movement.

Call your doctor at once if you have:

• severe or ongoing nausea, vomiting, or diarrhea (even while you are taking medication to prevent these effects);

• easy bruising, unusual bleeding, purple or red spots under your skin;

• low red blood cells (anemia) - pale skin, unusual tiredness, feeling light-headed or short of breath, cold hands and feet; or

• low white blood cell counts - fever, mouth sores, skin sores, sore throat, cough, trouble breathing.

You may need a blood transfusion if your blood counts get too low.

Common Inrebic side effects may include:

• nausea, vomiting;

• diarrhea; or

• anemia.

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 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.

Other drugs may interact with fedratinib, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.