Uses
What is dimethyl fumarate used for?
Dimethyl fumarate is commonly used to treat multiple sclerosis (MS). MS is a chronic condition where the immune system attacks and damages the protective coating around nerve cells, making it harder for the brain and body to work together. This can cause symptoms like trouble walking, fatigue, muscle weakness, numbness, and vision and memory problems. Dimethyl fumarate can treat the following relapsing forms of MS. 

Dimethyl fumarate may also be used for other conditions as determined by your health care provider.

How does dimethyl fumarate work (mechanism of action)?
Dimethyl fumarate may work by helping protect cells from damage caused by stress and supporting the body’s natural ability to repair and maintain itself.

How is dimethyl fumarate supplied (dosage forms)?

Brands and other names

• Tecfidera

Dosage forms and strengths

• 120 mg, 240 mg delayed-release oral capsules

How should I store dimethyl fumarate?
Dimethyl fumarate should be stored between 59 F and 86 F (15 C and 30 C). Store in a cool, dry place in the original container. Protect from light.

Side Effects
What are the most common side effects of dimethyl fumarate?
The most common side effects of dimethyl fumarate are listed below. Tell your health care provider if you have any of these side effects that bother you.

• Flushing, redness, rash, or itching
• Stomach problems (see below)

There may be other side effects of dimethyl fumarate that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of dimethyl fumarate?
While less common, the most serious side effects of dimethyl fumarate are described below, along with what to do if they happen.

Severe Allergic Reactions. Dimethyl fumarate may cause allergic reactions, which can be serious. Stop taking dimethyl fumarate and get help right away if you have any of the following symptoms of a serious allergic reaction.

• Breathing problems or wheezing
• Racing heart
• Fever or general ill feeling
• Swollen lymph nodes
• Swelling of the face, lips, mouth, tongue, or throat
• Trouble swallowing or throat tightness
• Itching, skin rash, or pale red bumps on the skin called hives
• Nausea or vomiting
• Dizziness, feeling lightheaded, or fainting
• Stomach cramps
• Joint pain

Stomach Problems. Nausea, vomiting, diarrhea, stomach pain, and upset stomach (or indigestion) are common side effects of dimethyl fumarate and may decrease over time. However, in some cases, serious stomach problems may also occur. These can include bleeding, ulcers (sores), blockage, and perforation (tears or holes) of the stomach or intestines. Call your health care provider right away if you have any of the following symptoms. 

• Stomach pain that does not go away
• Bright red stools or black, tarry stools
• Severe vomiting or diarrhea
• Coughing up blood or blood clots
• Vomiting blood or vomit that looks like coffee grounds

Progressive Multifocal Leukoencephalopathy (PML). People taking dimethyl fumarate may develop a rare brain disease called PML. It is caused by a virus called the JC virus. PML is very serious and can lead to death. Stop taking dimethyl fumarate and call your health care provider right away if you have any of the following symptoms of PML.

• Clumsiness or loss of coordination in the arms or legs
• Difficulty walking or speaking
• Facial drooping
• Vision problems
• Confusion
• Changes in thinking, memory, or personality
• Weakness on one side of your body that gets worse
• Seizures

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking dimethyl fumarate. Your health care provider will order blood tests to check your liver before and during treatment with dimethyl fumarate. Call your health care provider right away if you have any of the following symptoms of liver damage.

• Nausea or vomiting
• Stomach or belly pain
• Fever
• Weakness or unusual tiredness
• Itching
• Loss of appetite
• Light-colored poop
• Dark-colored urine (pee)
• Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Low White Blood Cell Levels (Lymphopenia). Dimethyl fumarate may cause low lymphocyte levels, also called lymphopenia or lymphocytopenia. Lymphocytes are a type of white blood cell. They help prevent infection. Having a low level of lymphocytes may increase your risk of infection. Your health care provider will order blood tests to check your lymphocyte levels before and during treatment with dimethyl fumarate. Tell your health care provider if you have any of the following symptoms of low lymphocyte levels.

• Fever, chills, or sweats
• Tiredness
• Sore throat, cough, or shortness of breath
• Mouth or throat sores
• Swollen lymph nodes

Herpes Zoster (Shingles). Dimethyl fumarate may cause serious cases of shingles, which may affect the eyes, brain, lungs, spinal cord, and other body systems. Call your health care provider right away if you have any of the following symptoms of shingles. 

• Swollen lymph nodes
• Fluid-filled blisters
• Stabbing or shooting pain (with or without a rash)
• Feeling like your skin is tingling or burning
• Fever or chills
• Headache
• Tiredness
• Upset stomach
• Eye symptoms such as blurry vision, sensitivity to light, or eye pain, rash, redness, or oozing

Other Serious Infections. Dimethyl fumarate may also increase the risk of other serious infections, including viral, fungal, and bacterial infections. This can happen even if your blood tests are normal. Talk to your health care provider about what kind of symptoms to look for and call your provider if you have any symptoms of infection.

Warnings & Precautions
Who should not use dimethyl fumarate?
Allergies to Ingredients. People who are allergic to any of the following should not take dimethyl fumarate.

• Dimethyl fumarate
• Tecfidera
• Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific dimethyl fumarate products they stock.

What should I know about dimethyl fumarate before using it?

Do not take dimethyl fumarate unless it has been prescribed to you by a health care provider. Take it as prescribed.

Do not share dimethyl fumarate with other people, even if they have the same condition as you. It may harm them.

Keep dimethyl fumarate out of the reach of children.

Your health care provider will order blood tests before and during treatment with dimethyl fumarate. Keep all appointments for follow-up and blood tests.

Swallow the capsule whole. Do not crush or chew the capsule. Do not open the capsule and mix the contents with food.

Flushing is a common side effect of dimethyl fumarate. You may feel warmth, redness, itching, and/or a burning feeling. If you have flushing that bothers you, try taking your medicine with food, which may help reduce flushing. You can also ask your health care provider if you can take a non-enteric-coated aspirin 30 minutes before taking dimethyl fumarate, which can help reduce flushing.

What should I tell my health care provider before using dimethyl fumarate?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if dimethyl fumarate is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

• Liver problems
• Low white blood cell counts
• Current or past infections
• Any other medical condition

Pregnancy. It is not known if or how dimethyl fumarate could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant. Your health care provider will let you know if you should take dimethyl fumarate while you are pregnant or trying to get pregnant.

Breastfeeding. It is not known if dimethyl fumarate passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should take dimethyl fumarate while breastfeeding.

Interactions
Does dimethyl fumarate interact with foods or drinks?
There are no known interactions between dimethyl fumarate and foods or drinks.

It is unknown if drinking alcohol will affect dimethyl fumarate, but both dimethyl fumarate and alcohol can cause liver damage. It is likely best to limit the amount of alcohol you drink while taking dimethyl fumarate.

Does dimethyl fumarate interact with other medicines (drug interactions)?

There are no known interactions between dimethyl fumarate and other medicines. Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

This may not be a complete list of medicines that can interact with dimethyl fumarate. Always check with your health care provider.

Overdose/Missed Dose
What should I do if I accidentally use too much dimethyl fumarate?
If you or someone else has used too much dimethyl fumarate, get medical help right away, or contact a Poison Control center.

What should I do if I miss a dose of dimethyl fumarate?
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.