Section 04 · Monograph

Dimethyl fumarate

Reviewed Nov 2026FDA label

TecfideraNrf2 activator

Indications

Treatment of relapsing forms of multiple sclerosis (MS) in adults, including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive diseaseFDA-labeled

Exact mechanism of therapeutic effect in MS is not fully understood
Dimethyl fumarate (DMF) and its primary metabolite monomethyl fumarate (MMF) activate the Nrf2 (nuclear factor erythroid 2-related factor 2) transcriptional pathway, which is involved in the cellular response to oxidative stress
MMF also acts as an agonist at the nicotinic acid (hydroxycarboxylic acid HCA2) receptor in vitro

Starting dose: 120 mg orally twice daily for 7 days
Maintenance dose: 240 mg orally twice daily thereafter
For persistent intolerability, temporary reduction to 120 mg twice daily may be considered; resume 240 mg twice daily within 4 weeks
Capsules must be swallowed whole and intact; do not crush, chew, or sprinkle capsule contents on food
May be taken with or without food; administration with food may improve tolerability
Non-enteric-coated aspirin (up to 325 mg) taken 30 minutes before dosing may reduce the incidence/severity of flushing

Known hypersensitivity to dimethyl fumarate or to any of the excipients of Tecfidera (reactions have included anaphylaxis and angioedema)

No clinically significant pharmacokinetic interactions identified; DMF and MMF are not substrates of, and do not meaningfully induce or inhibit, CYP450 enzymes
No interaction observed with interferon beta-1a or glatiramer acetate
Aspirin does not alter MMF pharmacokinetics
No relevant pharmacokinetic interaction with combined oral contraceptives
Effect of Tecfidera on immune response to live or live-attenuated vaccines has not been studied — avoid use of live vaccines

Flushing (~40%), typically mild-to-moderate; ~3% discontinue due to flushing
Abdominal pain (~18%), diarrhea (~14%), nausea (~12%), vomiting (~9%)
Pruritus (~8%) and rash (~8%)
Lymphopenia — mean lymphocyte counts fall ~30% during the first year; 6% of patients develop counts <0.5×10⁹/L
Progressive multifocal leukoencephalopathy (PML) — reported with prolonged moderate-to-severe lymphopenia
Serious infections including disseminated/atypical herpes zoster (encephalitis, meningoencephalitis, meningomyelitis)
Elevated hepatic transaminases; postmarketing cases of clinically significant liver injury
Anaphylaxis and angioedema, can occur after the first dose or at any time during treatment
Serious gastrointestinal events postmarketing (perforation, ulceration, hemorrhage, obstruction), mostly within first 6 months

Obtain CBC with lymphocyte count before initiating treatment
Repeat CBC with lymphocyte count at 6 months, then every 6–12 months thereafter, and as clinically indicated
Consider interrupting treatment if lymphocyte count remains <0.5×10⁹/L for more than 6 months
Obtain baseline serum aminotransferases, alkaline phosphatase, and total bilirubin; monitor periodically during treatment
Withhold treatment at the first sign or symptom suggestive of PML and evaluate; consider MRI as part of increased vigilance
Consider withholding treatment in patients with serious infection until resolution

Pregnancy: based on animal data, may cause fetal harm at high doses (embryofetal toxicity, developmental neurobehavioral impairment observed in animal studies at clinically relevant exposures)
Tecfidera Pregnancy Registry data (362 live births/stillbirths) showed a 3.6% (95% CI: 1.9–6.1) major birth defect rate, with no specific pattern of malformation identified
Encourage enrollment in the Tecfidera Pregnancy Registry for patients exposed during pregnancy
Lactation: no data on presence of dimethyl fumarate or monomethyl fumarate in human milk, or on effects on the breastfed infant or on milk production — weigh developmental/health benefits of breastfeeding against the mother's clinical need for the drug