Side Effects – Tecfidera® (dimethyl fumarate)

Tecfidera side effects

Treatment for relapsing multiple sclerosis (MS) means staying on therapy for as long as you and your doctor decide it's right for you. As a result, many people are rightfully concerned about the side effects of any given treatment. The side effects of Tecfidera have been documented in clinical studies for up to 4 years. In these studies, Tecfidera decreased white blood cell counts. Therefore, your doctor may do blood tests before starting treatment and from time to time while you take Tecfidera.

The most common side effects were flushing and stomach problems, which happened mainly at the start of treatment and usually decreased over time.

You should always talk to your doctor before taking Tecfidera if you're pregnant, interested in becoming pregnant, breastfeeding or plan to breastfeed. That's because it isn't known how taking Tecfidera would affect an unborn baby or if it passes into your breast milk. If you're pregnant while taking Tecfidera, talk to your doctor about enrolling in the Tecfidera Pregnancy Registry to monitor your health and the health of your baby.

Tecfidera Pregnancy Registry:

Common side effects

The most common side effects of Tecfidera in clinical studies were flushing and stomach problems. People tended to have symptoms at the start of treatment, and they usually decreased over time. If you experience persistent and/or severe flushing or stomach problems, you should speak with your healthcare provider, who may recommend taking Tecfidera with food which may help. You could have other side effects, so if you have any that bother you or don't go away, talk to your doctor or pharmacist. They may have advice for managing symptoms.

  • Common side effects
  • Flushing

    Symptoms are mostly mild to moderate and usually described as redness, itching, or rash

    Stomach problems

    Symptoms may include nausea, vomiting, diarrhea, stomach pain, or indigestion

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Tecfidera (dimethyl fumarate) is a prescription medicine used to treat people with relapsing forms of multiple sclerosis.

Important Safety Information

Important Safety Information and Indication

Before taking and while you take Tecfidera, tell your doctor about any low white blood cell counts or infections or any other medical conditions.

What are the possible side effects of Tecfidera?

Tecfidera may cause serious side effects including decreases in your white blood cell count. Your doctor may check your white blood cell count before you take Tecfidera and from time to time during treatment.

The most common side effects of Tecfidera include flushing and stomach problems. These can happen especially at the start of treatment and may decrease over time. Call your doctor if these symptoms bother you or do not go away.

These are not all the possible side effects of Tecfidera. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. For more information go to

Tell your doctor if you are pregnant or plan to become pregnant, or breastfeeding or plan to breastfeed. It is not known if Tecfidera will harm your unborn baby or if it passes into your breast milk. Also tell your doctor if you are taking prescription or over-the-counter medicines, vitamins, or herbal supplements.

For additional important safety information, please see full Prescribing Information and Patient Information. This is not intended to replace discussions with your doctor.