Dimethyl fumarate

Also known as Tecfidera

Key points about dimethyl fumarate

  • Dimethyl fumarate is used to treat multiple sclerosis.
  • Dimethyl fumarate is also called Tecfidera.
  • Find out how to take it safely and the possible side effects.
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Dimethyl fumarate is used to treat relapsing multiple sclerosis (MS). Dimethyl fumarate belongs to a group of medicines called disease-modifying therapies which help to slow or reduce the worsening of disability in people with relapsing remitting MS.

MS is caused by your immune system mistakenly attacking the myelin sheath in your brain and spinal cord, causing inflammation of the brain. Dimethyl fumarate decreases the inflammation in your brain and reduces nerve damage. Read more about multiple sclerosis.

  • In Aotearoa New Zealand dimethyl fumarate comes as capsules (120 mg and 240 mg).
  • The usual starting dose is 120 mg taken twice a day. After 7 days the dose is usually increased to 240 mg twice a day.
  • Always take dimethyl fumarate exactly as your doctor has told you. The pharmacy label will tell you how much to take, how often to take it and any special instructions.

  • Swallow the capsule whole with a glass of water. Don't crush, divide or dissolve the capsule or its contents.
  • You can take dimethyl fumarate with or without food. Taking it with food may reduce side effects, eg, flushing or vomiting (being sick).
  • Take your dose at about the same time each day, eg, in the morning during breakfast and at night during dinner.
  • If you forget to take your dose, take it as soon as you remember. But if it's nearly time for your next dose, take the next dose at the right time. Don't take extra doses to make up for a forgotten dose.

Here are some things to know when you're taking dimethyl fumarate. Other things may be important as well, so ask your healthcare provider what you should know about.

  • Increased risk of infections: Dimethyl fumarate weakens your body’s defence (immune) system, so you're more likely to pick up infections. It's important to avoid anyone who has chickenpox or shingles. Check with your doctor if you need to have vaccinations for these before you start taking dimethyl fumarate.
  • Pregnancy: There's no information on the use of dimethyl fumarate during pregnancy. Talk to your healthcare provider about contraception options for you and your partner. Tell your healthcare provider if you become pregnant while taking dimethyl fumarate.
  • Vaccines: Some vaccines shouldn't be taken after you've started taking dimethyl fumarate. Always check with your doctor or pharmacist first. It's safe for you to have the annual flu vaccine.
  • Other medicines: Dimethyl fumarate may interact with a few medicines and herbal supplements, so check with your doctor or pharmacist before starting dimethyl fumarate or before starting any new medicines, including those you may buy over-the-counter.

Like all medicines, dimethyl fumarate can cause side effects, although not everyone gets them. Often side effects improve as your body adjusts to the new medicine.

Side effects What should I do?
  • Flushing (going red in the face)
  • Feeling hot
  • Indigestion or upset stomach
  • Nausea (feeling sick).
  • These are quite common when you start dimethyl fumarate.
  • Try taking your dose with food.
  • Tell your doctor if they bother you.
  • Signs of an infection, eg, fever, cough, sore throat, diarrhoea (runny poo) or generally feeling weak and unwell
  • Tell your doctor immediately or phone Healthline on 0800 611 116.
Did you know that you can report a medicine side effect to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product.(external link)

The following links provide further information about dimethyl fumarate. Be aware that websites from other countries may contain information that differs from New Zealand recommendations.


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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Angela Lambie, Pharmacist, Auckland

Last reviewed: