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Tazverik Side Effects

Generic name: tazemetostat

Medically reviewed by Last updated on Sep 12, 2022.

Note: This document contains side effect information about tazemetostat. Some dosage forms listed on this page may not apply to the brand name Tazverik.

Applies to tazemetostat: oral tablet.

Serious side effects of Tazverik

Along with its needed effects, tazemetostat (the active ingredient contained in Tazverik) 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 tazemetostat:

More common

  • Bladder pain
  • bleeding gums
  • bloody or cloudy urine
  • body aches or pain
  • chest pain or tightness
  • cough
  • coughing up blood
  • difficult, burning, or painful urination
  • difficulty in breathing or swallowing
  • dizziness
  • ear congestion
  • fever or chills
  • frequent urge to urinate
  • headache
  • increased menstrual flow or vaginal bleeding
  • loss of voice
  • lower back or side pain
  • muscle or bone pain
  • nosebleeds
  • pale skin
  • prolonged bleeding from cuts
  • red or black, tarry stools
  • red or dark brown urine
  • redness, itching, pain, swelling, tenderness, or warmth on the skin
  • sneezing
  • sore throat
  • stuffy or runny nose
  • unusual bleeding or bruising
  • unusual tiredness or weakness

Less common

  • Confusion
  • fast heartbeat
  • lightheadedness or fainting
  • painful blisters on the trunk of the body
  • rapid, shallow breathing


  • General feeling of illness
  • hoarseness
  • sores, ulcers, or white spots on the lips or in the mouth
  • swollen glands
  • weight loss
  • yellow skin and eyes

Other side effects of Tazverik

Some side effects of tazemetostat 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 tazemetostat: oral tablet.


Very common (10% or more): Hemoglobin decreased (49%), decreased lymphocytes (36%), white blood cell count decreased (19%), hemorrhage (e.g., wound hemorrhage, rectal hemorrhage, pulmonary hemorrhage, hemorrhage intracranial, cerebral hemorrhage, hemoptysis) (18%), anemia (16%), partial thromboplastin time increased (15%)[Ref]


Very common (10% or more): Triglycerides increased (36%), glucose increased (33%), sodium decreased (30%), phosphate decreased (28%), anorexia (26%), albumin decreased (23%), alkaline phosphatase increased (23%), potassium decreased (20%), weight loss (16%), calcium decreased (16%), glucose decreased (16%), potassium increased (12%)[Ref]


Very common (10% or more): Aspartate aminotransferase increased (18%), alanine aminotransferase increased (14%)[Ref]


Uncommon (0.1% to 1%): Secondary malignancies (e.g., myelodysplastic syndrome [MDS], acute myeloid leukemia [AML])[Ref]


Very common (10% or more): Cough (18%), dyspnea/dyspnea exertional (16%)[Ref]


Very common (10% or more): Pain (e.g., tumor pain, pain in extremity, non-cardiac chest pain, flank pain, back pain, arthralgia, bone pain, cancer pain, musculoskeletal pain, myalgia, neck pain) (52%), fatigue/asthenia (47%)[Ref]


The most common adverse reactions (20% or greater) were pain, fatigue, nausea, decreased appetite, vomiting, and constipation.[Ref]

Nervous system

Very common (10% or more): Headache (18%)[Ref]


Very common (10% or more): Creatinine increased (14%)[Ref]


Very common (10% or more): Nausea (36%), vomiting (24%), constipation (21%), diarrhea (16%), abdominal pain (13%)[Ref]


1. "Product Information. Tazverik (tazemetostat)." Epizyme, Inc (2020):

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.