Understanding safety and potential side effects

It's important to talk to your healthcare provider if you've had an allergic reaction to dimethyl fumarate, VUMERITY® (diroximel fumarate), or any of its ingredients. You should also discuss the serious side effects associated with VUMERITY, including:

Allergic reactions

Allergic reactions (such as welts, hives, swelling of the face, lips, mouth or tongue, or difficulty breathing).


PML is a rare brain infection that usually leads to death or severe disability over a period of weeks or months. Tell your healthcare provider right away if you get any of these symptoms of PML:

  • weakness on one side of the body that gets worse
  • clumsiness in your arms or legs
  • vision problems
  • changes in thinking and memory
  • confusion
  • personality changes


Herpes zoster infections (shingles)

Herpes zoster infections (commonly known as shingles), including infections of the central nervous system.

Decreases in your white blood cell count

Your healthcare provider should check your white blood cell count before you start VUMERITY, 6 months after starting treatment, and then every 6-12 months thereafter as they feel necessary.

Liver problems

Your healthcare provider should do blood tests to check your liver function before you start taking VUMERITY and during treatment if needed. Tell your healthcare provider right away if you get any symptoms of a liver problem during treatment, including:

  • severe tiredness
  • loss of appetite
  • pain on the right side of your stomach
  • dark or brown (tea color) urine
  • yellowing of your skin or the white part of your eyes

Your healthcare provider should do a blood test before you start treatment with VUMERITY and while you’re on therapy.

Most common side effects of VUMERITY

The most common side effects of VUMERITY include:

  • flushing, redness, itching, or rash
  • nausea, vomiting, diarrhea, stomach pain, or indigestion
  • Flushing and stomach problems are the most common reactions, especially at the start of therapy, and may decrease over time. Taking VUMERITY with food (avoid high-fat, high-calorie meal or snack) may help reduce flushing. Call your healthcare provider if you have any of these symptoms and they bother you or do not go away. Ask your healthcare provider if taking aspirin before taking VUMERITY may reduce flushing

These are not all the possible side effects of VUMERITY. Call your healthcare provider for medical advice about side effects.