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Fedratinib Side Effects

Medically reviewed by Last updated on May 4, 2022.

For the Consumer

Applies to fedratinib: oral capsule


Oral route (Capsule)

Warning: Encephalopathy including Wernicke'sSerious and fatal encephalopathy, including Wernicke’s, has occurred in patients treated with fedratinib. Wernicke’s encephalopathy is a neurologic emergency. Assess thiamine levels in all patients prior to starting fedratinib, periodically during treatment, and as clinically indicated. Do not start fedratinib in patients with thiamine deficiency; replete thiamine prior to treatment initiation. If encephalopathy is suspected, immediately discontinue fedratinib and initiate parenteral thiamine. Monitor until symptoms resolve or improve and thiamine levels normalize.

Side effects requiring immediate medical attention

Along with its needed effects, fedratinib may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking fedratinib:

More common

  • Black, tarry stools
  • bleeding gums
  • blood in the urine or stools
  • chills
  • cough
  • fever
  • lower back or side pain
  • painful or difficult urination
  • pale skin
  • pinpoint red spots on the skin
  • sore throat
  • troubled breathing with exertion
  • ulcers, sores, or white spots in the mouth
  • unusual bleeding or bruising
  • unusual tiredness or weakness

Less common

  • Bladder pain
  • cloudy urine
  • confusion
  • difficult, burning, or painful urination
  • drowsiness
  • frequent urge to urinate
  • lower back or side pain
  • shakiness and unsteady walk
  • trouble remembering
  • uncontrolled eye movements
  • unsteadiness, trembling, or other problems with muscle control or coordination

Side effects not requiring immediate medical attention

Some side effects of fedratinib may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

For Healthcare Professionals

Applies to fedratinib: oral capsule


Very common (10% or more): Anemia (34%), neutropenia (23%), thrombocytopenia (12%)[Ref]


Very common (10% or more): Muscle spasms (12%), pain in extremity (10%)

Common (1% to 10%): Bone pain[Ref]


Very common (10% or more): Hyponatremia (26%)

Common (1% to 10%): Weight gain[Ref]


Common (1% to 10%): Urinary tract infection, dysuria[Ref]


Very common (10% or more): Elevated ALT (43%), elevated AST (40%)[Ref]


Very common (10% or more): Fatigue/asthenia (19%)[Ref]

Nervous system

Common (1% to 10%): Encephalopathy (including Wernicke's), headache, dizziness[Ref]


Very common (10% or more): Blood creatinine increased (10%)[Ref]


Very common (10% or more): Diarrhea (66%), nausea (62%), vomiting (39%), amylase and/or lipase elevations (10%)[Ref]


1. "Product Information. Inrebic (fedratinib)." Celgene Corporation (2019):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.