Skip to main content

Dimethyl fumarate

Generic name: dimethyl fumarate [ dye-METH-il-FUE-mar-ate ]
Brand names: Tecfidera, Tecfidera Starter Pack
Dosage form: oral delayed release capsule (-; 120 mg; 240 mg)
Drug class: Selective immunosuppressants

Medically reviewed by on Nov 15, 2023. Written by Cerner Multum.

What is dimethyl fumarate?

Dimethyl fumarate is used to treat relapsing forms of multiple sclerosis in adults (including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease).

Dimethyl fumarate may also be used for purposes not listed in this medication guide.

Dimethyl fumarate side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Dimethyl fumarate may cause a serious brain infection that can lead to disability or death. Call your doctor right away if you have problems with speech, thought, vision, or muscle movement. These symptoms may start gradually and get worse quickly.

Also call your doctor at once if you have:

Common side effects of dimethyl fumarate may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Dimethyl fumarate may cause a serious brain infection that can lead to disability or death. Call your doctor right away if you have problems with speech, thought, vision, or muscle movement. These symptoms may start gradually and get worse quickly.

Before taking this medicine

You should not use dimethyl fumarate if you have had a severe allergic reaction to dimethyl fumarate or diroximel fumarate (Vumerity).

Tell your doctor if you have ever had:

Tell your doctor if you are pregnant or breastfeeding.

If you are pregnant, your name may be listed on a pregnancy registry to track the effects of dimethyl fumarate on the baby.

Dimethyl fumarate is not approved for use by anyone younger than 18 years old.

How should I take dimethyl fumarate?

Your doctor will perform blood tests to make sure you do not have conditions that would prevent you from safely using dimethyl fumarate.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

You may take dimethyl fumarate with or without food. Taking the medicine with food may help prevent flushing (sudden warmth, redness, or tingly feeling).

Swallow the capsule whole and do not crush, chew, break, or open it.

While using dimethyl fumarate, you will need frequent blood tests.

Store this medicine in the original container at room temperature, away from moisture, heat, and light.

Dimethyl fumarate dosing information

Usual Adult Dose for Multiple Sclerosis:

Initial dose: 120 mg orally twice a day for 7 days
Maintenance dose: 240 mg orally twice a day

Use: For the treatment of relapsing forms of multiple sclerosis, to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking dimethyl fumarate?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect dimethyl fumarate?

Other drugs may affect dimethyl fumarate, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Popular FAQ

Yes, Tecfidera does suppress the immune system. Although experts are not sure exactly how Tecfidera does this, Tecfidera has been associated with reductions in lymphocyte counts, and several serious opportunistic viral infections, such as progressive multifocal leukoencephalopathy and herpes zoster, as well as uncommon fungal and bacterial infections. Continue reading

There does not appear to be any rebound disease repercussions associated with stopping Tecfidera abruptly, unlike some other MS drugs such as Tysabri or Gilenya. Studies have shown the majority of patients taking Tecfidera discontinue or switch to another treatment within two years. Continue reading

40% of people report flushing as a side effect of Tecfidera and although experts aren’t sure how Tecfidera causes flushing they suggest it may be due to one of the pathways affected by Tecfidera called HCAR2. When the metabolite of Tecfidera, MMF binds to HCAR2, it induces prostanoid-forming enzymes in different cell types. These enzymes form prostaglandins which, in addition to other effects, signal capillaries to open, which causes flushing. Continue reading

Although there is no direct interaction between alcohol and Tecfidera (dimethyl fumarate), you should not drink excessive quantities of alcohol while you are taking Tecfidera, because it may increase the risk of side effects such as inflammation of the stomach (gastritis), especially in those with a history of stomach problems. You should avoid drinking alcohol, especially strong spirits, for at least an hour after taking Tecfidera; however, one glass of alcohol, now and then at a different time of day to your Tecfidera dose is considered OK. Continue reading

Gilenya and Tecfidera are both disease-modifying oral medications approved for the treatment of MS. Both are equally effective although Tecfidera is more likely than Gilenya to be discontinued within 24 months. Gilenya is approved to treat adults and children aged 10 and older and Tecfidera is only approved for adults over the age of 18. Common side effects of Gilenya include heart rhythm disturbances, diarrhea, infections, and elevations in liver enzymes and common side effects of Tecfidera include flushing, gastrointestinal disturbances, and infections. Tecfidera is slightly more expensive than Gilenya. Continue reading

Tecfidera can be taken for as long as it continues to have a clinical benefit and you are not experiencing intolerable or severe side effects. Continue reading

Weight gain or weight loss is not a recognized side effect of Tecfidera and it is not documented in the prescribing information for Tecfidera which reports side effects that occur in clinical trials at a 2% higher incidence than placebo. However, anecdotally blog sites report weight gains with Tecfidera of anywhere from 5-6lbs to up to 25 pounds, but there are also people who report weight loss of up to 14 pounds. Continue reading

Tecfidera starts to work within 24 weeks; however, it may take up to two years for the full effects to be seen. Continue reading

Yes, Tecfidera can cause low lymphocytes. In controlled trials, lymphocyte counts decreased by an average of 30% during the first year of treatment with Tecfidera but remained stable thereafter. When Tecfidera was discontinued, lymphocyte counts increased, although they did not return to pre-treatment levels. Continue reading

View more FAQ

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.