Dimethyl Fumarate (Oral)

Dimethyl fumarate is used in multiple sclerosis patients who are suffering from the relapsing/remitting form of the disease.


Dimethyl fumarate is used in the treatment of multiple sclerosis patients who have been diagnosed with the relapsing/remitting (RRMS) form of the condition. The medication will not provide a cure for multiple sclerosis, but it can help to slow some of the more disabling side effects of the disease and reduce the number of relapses suffered by the patient.

Dimethyl fumarate comes in delayed-release capsule form and is only available from your GP or treating specialist on prescription.

In the US, dimethyl fumarate is sold under the brand name Tecfidera.

Conditions treated

  • Relapsing/remitting multiple sclerosis (RRMS)

Type of medicine

  • Slow-release oral capsule

Side effects

Together with the effects that it is designed to give, dimethyl fumarate may cause a few unwanted side effects. Not everyone using the drug will experience these side effects, but if you do, you should seek medical attention.

If you notice any of the effects listed below when you begin using dimethyl fumarate, you should contact your GP or specialist immediately:

  • White spots, sores, or ulcers, on the lips or in the mouth
  • Unusual bleeding or bruising
  • Swollen glands
  • Sore throat
  • Shortness of breath
  • Redness of the neck, face, arms, and occasionally of the upper chest
  • Pain in the lower back or side
  • Hoarseness or a cough
  • Fever or chills
  • Feeling unusually tired or weak
  • A feeling of warmth
  • Difficult or painful urination
  • Chest pains
  • Black, tarry stools

There are some side effects that dimethyl fumarate sometimes causes that often resolve by themselves, as your body acclimatizes to the medicine. In this case, you will not need to attend your doctor unless the effects become especially bothersome or persistent. However, you may want to ask your GP or MS nurse for advice on how to manage any effects that occur - or if you have any questions about them.

  • Vomiting
  • Stomach discomfort or upset
  • Rash
  • Nausea
  • Itching skin
  • Indigestion
  • Heartburn
  • Diarrhea
  • Belching
  • Acid or sour stomach
  • Abdominal or stomach pain

Some people taking dimethyl fumarate experience other effects that may not be mentioned here. If you begin to have other odd effects, you should check with your specialist or GP.


You must take dimethyl fumarate exactly as you have been instructed by your GP or MS nurse. Do not exceed the prescribed dose, take the drug more frequently, or take it for a longer period than you have been told to. If you do, you risk increasing any side effects that the drug may cause.

When you receive your prescription of dimethyl fumarate, you will also be given an information leaflet. Be sure to read the information thoroughly, and ask your GP if there is anything you do not understand.

You must swallow dimethyl fumarate capsules in one piece. Do not break them open, crush them, or chew them. You may take your medication with food or just with a glass of water if you prefer. However, you may experience less skin flushing if you take dimethyl fumarate with a meal.

The dose of dimethyl fumarate that you are prescribed will vary between patients. You should follow the directions given to you by your doctor or those on the product label. The dose levels given in this guide are only based on the average. If your prescribed dose is different, you should not alter it unless you are expressly told to by your GP.

Your prescribed dose will depend on the strength of the preparation. The amount of dimethyl fumarate you take daily, the time you leave between doses, and the duration of your course of treatment will all depend on the extent of your RRMS and how your body reacts to the drug.

Delayed-release capsules for RRMS:

  • Adults: To begin with, take 120 mg, twice daily. After one week, your dose may be upped to 240 mg twice daily, as per your GP's instructions.
  • Children: Your child's specialist will give you instructions on the dose and use of this drug.

If you forget to take one of your doses of dimethyl fumarate, try to take it as soon as you can. If it is nearly time for your second dose, leave out the one you have forgotten and return to your usual dosing schedule. Never take twice the amount you have been prescribed.


Some medications should not be used at the same time as each other. This is because doing so could cause an interaction between the two drugs. If this applies to your current medicine and dimethyl fumarate, your GP may change your dose or suggest ways in which you can prevent or manage any interactions that might occur between the two drugs.

Remember to tell your treating physician if you are taking any other prescription or over the counter medicines, before you begin using dimethyl fumarate.

Some drugs should not be used when you are eating certain foodstuffs, when you are drinking alcohol, or if you are using tobacco. If you smoke, drink alcohol, or have a preference for certain food groups, have a chat with your GP to make sure that this will not affect your use of dimethyl fumarate.


When deciding whether or not to use dimethyl fumarate, it is important to take into consideration the risks as well as the benefits. This decision is one that you can make following discussions with your GP or MS specialist.


Before you begin using dimethyl fumarate, you must tell your GP if you have ever noticed any strange or allergic reactions to dimethyl fumarate or any prescription or non-prescription medicines. You should also mention if you have any known allergies to particular food groups, animal products, food colors or preservatives.

Pregnancy and breastfeeding

Research has not shown that dimethyl fumarate has any adverse effects on the unborn baby. However, you may wish to discuss with your doctor the safety of using this drug if you are pregnant or if you are intending to become pregnant while you are taking it.

It also appears that there is no research to show whether dimethyl fumarate passes into a mother's breast milk. However, to err on the side of caution you may want to consider using an alternative method of feeding your infant while you are taking this drug.

Medical history

Some historical or existing health conditions in addition to relapsing/remitting multiple sclerosis may affect how dimethyl fumarate works. You should have a full and frank discussion with your GP about your current and historical medical history before you begin using dimethyl fumarate.

You should not use dimethyl fumarate if you are suffering from any form of infection or if you have a condition called lymphopenia, which causes the level of white cells in your blood to fall too low. Using this medication under these circumstances can make your condition worse. If possible, you should avoid contact with people who have coughs, colds or other forms of infections. If you begin to feel feverish or think you are developing a chill, or if you have a cough or hoarseness, pain in your side of lower back, or if you find urinating difficult or painful, you should consult your GP straightaway.

During the course of your treatment with dimethyl fumarate, you will need to attend your GP or MS specialist for blood tests to see that the drug is working correctly and to measure any side effects it may be causing.

Some patients who are taking dimethyl fumarate experience a degree of skin flushing. This side effect usually disappears once your body gets used to the drug. However, you should notify your doctor immediately if you notice a burning or itching sensation, warmth or reddening of the skin on your arms, upper chest, face, or neck while you are using dimethyl fumarate.


You should store your supply of dimethyl fumarate in the sealed container it is dispensed in. Keep the medicine out of direct sunlight and away from heat sources. Do not allow the medicine to get wet. Do not freeze or refrigerate the medicine.

Be sure to put the dimethyl fumarate capsules well away from children and pets. The capsules can easily be mistaken for candy and may be eaten by curious children. If you think a pet has eaten any of your medicine, you should consult your vet as soon as possible.

Do not keep any out of date or unwanted dimethyl fumarate capsules. Once you have opened the container of capsules, you must discard any that you have not used after a maximum of 90 days. Do not throw unwanted or outdated medication down the drain or flush them down the toilet. Keep unused capsules in their container, wrap the container in a bag, seal it, and place it at the bottom of your garbage can where it cannot be reached by small children or pets.


Dimethyl fumarate is used to treat patients suffering from relapsing/remitting multiple sclerosis. Although this drug does not offer a cure for the disease, it can help to slow down the progression of the condition, and it is effective in reducing the number of relapses suffered.

There are a few side effects that may be noted by patients taking dimethyl fumarate, but it is generally a very safe drug to use and it has no notable drug interactions. However, dimethyl fumarate has a dampening effect on the patient's immune response, which can make them more susceptible to contracting infections. This effect is further exacerbated by the action of the drug in lowering the amount of white cells in the blood. It is therefore important that you try to avoid environments where you are likely to be exposed to potential sources of infection.

While you are taking dimethyl fumarate, you must attend your GP or MS specialist for regular update appointments. You will also be required to have blood tests to allow your treating physician to monitor the effect that the drug is having on your body. Dimethyl fumarate is generally prescribed for long-term use in MS patients.


[https: //www.mayoclinic.org/drugs-supplements/dimethyl-fumarate-oral-route/description/drg-20060904]

[https: //www.webmd.com/drugs/2/drug-163864/dimethyl-fumarate-oral/details]

[https: //www.mstrust.org.uk/a-z/tecfidera-dimethyl-fumarate?gclid=EAIaIQobChMIqZf045-b2AIVw7vtCh0bbgGgEAAYASAAEgJUrPD_BwE]

Last Reviewed:
March 26, 2018
Last Updated:
April 23, 2018