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Bafiertam Side Effects

Generic name: monomethyl fumarate

Medically reviewed by Last updated on May 16, 2022.

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

For the Consumer

Applies to monomethyl fumarate: oral capsule delayed release

Side effects requiring immediate medical attention

Along with its needed effects, monomethyl fumarate (the active ingredient contained in Bafiertam) 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 monomethyl fumarate:

Less common

  • Chills
  • cough
  • fever
  • hoarseness
  • lower back or side pain
  • painful or difficult urination

Incidence not known

  • Chest tightness
  • dark urine
  • difficulty swallowing
  • dizziness
  • fast heartbeat
  • hives, itching, skin rash
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals
  • loss of appetite
  • painful blisters on trunk of body
  • right upper stomach tenderness
  • trouble with breathing
  • unusual tiredness or weakness
  • weight loss
  • yellow eyes or skin

Side effects not requiring immediate medical attention

Some side effects of monomethyl fumarate 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

  • Diarrhea
  • feeling of warmth
  • nausea
  • redness of the face, neck, arms, and occasionally, upper chest
  • stomach pain
  • vomiting

Less common

For Healthcare Professionals

Applies to monomethyl fumarate: oral delayed release capsule


Common (1% to 10%): Lymphopenia[Ref]


Frequency not reported: Anaphylaxis, angioedema[Ref]


Frequency not reported: Herpes zoster, disseminated herpes zoster, herpes zoster ophthalmicus, herpes zoster meningoencephalitis, herpes zoster meningomyelitis, herpes simplex virus, West Nile virus, cytomegalovirus, Candida, Aspergillus, Nocardia, Listeria monocytogenes, Mycobacterium tuberculosis)[Ref]


Common (1% to 10%): Albumin urine present[Ref]


Common (1% to 10%): Aspartate aminotransferase increased

Frequency not reported: Liver injury[Ref]

Nervous system

Frequency not reported: Progressive Multifocal Leukoencephalopathy (PML)[Ref]


Very common (10% or more): Flushing (40%)[Ref]


Common (1% to 10%): Pruritus, rash, erythema[Ref]


Very common (10% or more): Abdominal pain (18%), diarrhea (14%), nausea (12%)

Common (1% to 10%): Vomiting, dyspepsia[Ref]

Frequently asked questions


1. "Product Information. Retevmo (selpercatinib)." Lilly, Eli and Company (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.