Tecfidera (dimethyl fumarate) can cause side effects that range from mild to serious. More common side effects include flushing and abdominal pain. If side effects from Tecfidera become difficult to tolerate, talk with your doctor about coping tips or other treatment options.

Tecfidera is a prescription medication that’s used to treat the following conditions in adults:

Keep reading to learn about the common, mild, and serious side effects Tecfidera can cause. To learn more about Tecfidera, including its uses, dosage, and cost, read this Tecfidera overview.

Tecfidera can cause certain side effects, some of which may be more common than others. These side effects may be temporary, lasting a few days to weeks. Talk with your doctor if side effects do not go away, get worse, or become too difficult for you to tolerate.

Tecfidera’s commonly reported side effects include:

For more information about some of these side effects, see the “Tips for managing side effects” section.

Mild side effects have been reported with Tecfidera. These include:

  • flushing
  • abdominal pain
  • problems with digestion, such as nausea, diarrhea, vomiting, and indigestion
  • itching
  • skin rash, redness, or discoloration
  • albumin (a type of protein) in the urine, which can be a sign of kidney problems

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And don’t stop using Tecfidera unless your doctor recommends it.

Tecfidera may cause mild side effects other than the ones listed above. See the Tecfidera prescribing information for details.

For more information about some of these side effects, see the “Tips for managing side effects” section.

Tecfidera may cause serious side effects. The following list may not include all possible serious side effects of the drug. For more information, you can refer to Tecfidera’s prescribing information.

If you develop serious side effects while taking Tecfidera, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported and their symptoms include:

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Sharing your experience helps make medication safer for everyone by giving doctors and researchers more information about how the drug works in real life. If you develop a side effect while taking Tecfidera and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.

Allergic reaction

For some people, Tecfidera can cause an allergic reaction.

But it’s not clear whether this side effect occurred in the drug’s studies.

In general, symptoms of an allergic reaction can be mild or serious.

What might help?

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms and can determine whether you should keep taking Tecfidera.

If you have symptoms of a severe allergic reaction, such as swelling or difficulty breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Tecfidera, they may have you switch to a different treatment.

Here are answers to a few frequently asked questions about Tecfidera’s side effects.

Can Tecfidera affect my teeth?

It isn’t likely. Tooth-related side effects weren’t reported in studies of Tecfidera.

MS, which Tecfidera is used to treat, may cause tooth-related problems. This is because the symptoms of this condition can make it difficult to care for your teeth.

For example, MS can cause tingling or numbness in your hands. These symptoms can make it hard to floss or brush your teeth regularly. And this can lead to problems such as tooth cavities.

Other medications used to treat MS are known to have tooth-related side effects. Examples include Aubagio (teriflunomide) and Avonex (interferon beta-1a). These medications can cause side effects such as toothache and gum disease.

Talk with your doctor about ways to lower your risk of tooth-related problems with Tecfidera and MS.

How long do side effects of Tecfidera typically last?

It depends. Most side effects of Tecfidera are mild and should be temporary. But, there may be serious side effects, such as progressive multifocal leukoencephalopathy (PML), which can cause lasting effects.

If you experience any side effects that are ongoing or bothersome, talk with your doctor or pharmacist.

Does Tecfidera cause long-term side effects?

It’s possible. Long-term side effects include those that may start at any time you’re taking a drug, even if you’ve taken it for a long time. It also includes side effects that may not go away even after you stop taking the drug.

Examples of long-term side effects reported in Tecidera’s studies include:

  • progressive multifocal leukoencephalopathy (PML)
  • high level of liver enzymes (proteins), which can be a sign of liver damage

Talk with your doctor to learn more about the possible side effects of Tecfidera and how long they may last.

While taking Tecfidera, you may be able to take steps to make side effects easier to manage.

If you have problems with side effects, they do not go away, or they become worse, talk with your doctor or pharmacist. They can discuss options for managing side effects or other available treatment options.

Flushing

Flushing is the most common side effect of Tecfidera. With flushing, you may have itching, warmth, or a burning sensation on your face or neck. Flushing caused by Tecfidera usually goes away with time.

If you have flushing while taking Tecfidera, these tips may help ease this side effect:

  • Take Tecfidera with food. In this case, you’ll take Tecfidera after you’ve eaten.
  • Take uncoated aspirin at least 30 minutes before you take Tecfidera.

If this side effect is bothersome for you, talk with your doctor. They can recommend other ways to reduce your flushing.

Abdominal pain

Abdominal pain is a common side effect of Tecfidera. It mostly occurs right after taking the drug for the first time and should go away as your body gets used to the drug. Abdominal pain can also be a symptom of other side effects from Tecfidera, such as nausea or indigestion.

You may find home remedies for abdominal pain, such as drinking more water and avoiding spicy or greasy foods, helpful for managing your symptoms.

Talk with your doctor if you have bothersome abdominal pain while taking Tecfidera. They can suggest ways to ease this side effect.

Progressive multifocal leukoencephalopathy (PML)

PML is a rare but serious side effect of Tecfidera. It happens when a certain virus attacks the central nervous system. PML causes symptoms such as:

Tell your doctor right away if you have symptoms of PML. They’ll run tests to see if you have this condition. If you test positive for PML, your doctor will likely recommend that you stop taking Tecfidera. And they’ll advise on other treatments you may need for the symptoms of this condition.

Before taking Tecfidera, discuss your health history with your doctor. Tecfidera may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

  • weakened immune system or a low level of lymphocytes
  • history of gastrointestinal (GI) problems, including ulcers or obstructions in the GI tract
  • liver problems
  • chronic or reoccurring infection, such as shingles
  • previous allergic reaction to this or a similar drug
  • pregnancy or breastfeeding
  • alcohol consumption

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.