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Tecfidera Side Effects

Generic name: dimethyl fumarate

Medically reviewed by Last updated on Sep 21, 2022.

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


Common side effects of Tecfidera include: infection, abdominal pain, and flushing. Other side effects include: increased serum aspartate aminotransferase, pruritus, skin rash, vomiting, lymphocytopenia, and erythema of skin. Continue reading for a comprehensive list of adverse effects.

Applies to dimethyl fumarate: oral capsule delayed release.

Serious side effects of Tecfidera

Along with its needed effects, dimethyl fumarate (the active ingredient contained in Tecfidera) 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 dimethyl fumarate:

More common

  • Chills
  • cough
  • feeling of warmth
  • fever
  • hoarseness
  • lower back or side pain
  • painful or difficult urination
  • redness of the face, neck, arms, and occasionally, upper chest

Incidence not known

  • Black, tarry stools
  • chest pain
  • difficulty with swallowing
  • dizziness
  • fast heartbeat
  • hives, itching, or skin rash
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals
  • painful blisters on the trunk of the body
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • swollen glands
  • tightness in the chest
  • trouble breathing
  • unusual bleeding or bruising
  • unusual tiredness or weakness

Other side effects of Tecfidera

Some side effects of dimethyl 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

Less common

For Healthcare Professionals

Applies to dimethyl fumarate: oral delayed release capsule.


Common (1% to 10%): Lymphopenia, leucopenia, WBC decreased

Frequency not reported: Eosinophilia[Ref]


Very common (10% or more): Ketones in urine, 1+ or greater (45%), 1,25-dihydroxyvitamin D decreased (25%), (PTH) increased (29%)[Ref]


Very common (10% or more): Flushing (34% to 40%)

Common (1% to 10%): Hot flush[Ref]

The incidence of flushing was highest early in the course of treatment (primarily in month 1) and usually decreased over time. The majority of events were mild to moderate in severity.[Ref]


Common (1% to 10%): Feeling hot[Ref]


Very common (10% or more): Diarrhea (14%), nausea (12%), abdominal pain (upper) (10%), abdominal pain (9% to 18%)

Common (1% to 10%): Vomiting, dyspepsia, gastritis, gastrointestinal disorder, gastroenteritis[Ref]

The incidence of gastrointestinal events was highest early in the course of treatment (primarily in month 1) and usually decreased over time.[Ref]


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


Increases in hepatic transaminases (AST and ALT) generally occurred during the first six months of treatment, and most patients had levels less than 3 times the upper limit of normal (ULN).[Ref]

Common (1% to 10%): AST increased, ALT increased[Ref]

Nervous system

Common (1% to 10%): Burning sensation[Ref]


Uncommon (0.1% to 1%): Serious flushing[Ref]


Common (1% to 10%): Proteinuria (albumin)[Ref]

Frequently asked questions


1. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

2. Cerner Multum, Inc. "Australian Product Information." O 0

3. "Product Information. Tecfidera (dimethyl fumarate)." Biogen (2013):

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.