Common drugs: Dimethyl fumarate profile

How does dimethyl fumarate work?

Dimethyl fumarate has immunomodulatory and antioxidant effects. The exact mechanism of action is unclear. The active ingredient appears to upregulate antioxidant genes and influence the immune system via activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) transcription pathway.

What is dimethyl fumarate used for?

Dimethyl fumarate (Tecfidera®) is used in adults and adolescents aged 13 years and older with relapsing-remitting multiple sclerosis (MS). It is considered first-line therapy for mild to moderate cases. Dimethyl fumarate (Skilarence®, formerly Fumaderm®) is also used for moderate to severe psoriasis vulgaris, particularly when topical therapy has not been sufficiently effective. Here, too, it is considered first-line therapy.

How is dimethyl fumarate dosed?

For MS, dimethyl fumarate is dosed at 120 mg twice daily for the first week. The maintenance dose from the second week onward is 240 mg twice daily. For psoriasis, the dose is started at a lower level (30 mg once daily in the evening) and increased more slowly (over four weeks). The maintenance dose for psoriasis can be up to 720 mg daily, depending on response and tolerability.

For better tolerability, oral dosage forms of dimethyl fumarate should be taken whole with or after a meal.

What side effects can dimethyl fumarate have?

Although dimethyl fumarate has immunomodulatory effects, the infection rate in clinical trials was no higher than with placebo. Very common adverse effects include diarrhea, nausea and abdominal pain, flushing, lympho- and leukopenia, and ketone bodies in the urine. Common adverse effects include headache, fatigue, itching and rash, loss of appetite, mild fever, or flu-like symptoms. Serious side effects such as impaired liver function, severe allergic reactions, or progressive multifocal leukoencephalopathy (PML) may occur rarely. Cases of Fanconi syndrome have also been reported. Patients receiving dimethyl fumarate are advised to have regular blood count, liver function, and kidney function tests.

What interactions are possible?

During treatment with dimethyl fumarate, the concomitant use of other fumaric acid derivatives, both systemic and topical, should be avoided. Concomitant use of nephrotoxic drugs may increase the risk of renal adverse effects. Combinations of dimethyl fumarate with antineoplastic or immunosuppressive therapies have not been studied and should therefore be used with caution. This also applies to Skilarence in combination with other systemic psoriasis therapies. The use of live vaccines should be limited to exceptional cases when taking dimethyl fumarate.

Patients may consume alcohol while taking dimethyl fumarate, but should avoid high-proof alcohol, as this may affect the galenic properties and increase the risk of gastrointestinal side effects.

What are the contraindications?

Tecfidera is absolutely contraindicated in suspected or confirmed PML and severe lymphopenia. Skilarence is contraindicated in severe gastrointestinal disorders, severe liver or kidney impairment, and during pregnancy and breastfeeding. Caution is also advised in PML and severe lymphopenia. Skilarence is contraindicated in cases of severe kidney or liver impairment, while caution is indicated with Tecfidera.

Can dimethyl fumarate be used during pregnancy and breastfeeding?

In animal studies, dimethyl fumarate has been shown to be reproductively toxic. Its use during pregnancy is contraindicated in psoriasis. In MS, dimethyl fumarate should be avoided during pregnancy and used only when clearly needed, when the potential benefit outweighs the potential risk to the fetus.

Embryotox , the Pharmacovigilance and Advisory Center for Embryonic Toxicology at the Charité Hospital in Berlin, states that treatment with fumaric acid esters can be continued until a positive pregnancy test is achieved. No teratogenicity has been observed in pregnancies observed to date. MS patients should be switched to interferon-β or glatiramer acetate, and patients with psoriasis should be switched to topical corticoids or, if these are insufficient, to prednisolone or cyclosporine.

It is unknown whether dimethyl fumarate or its metabolites are excreted in breast milk. According to the prescribing information, breastfeeding can be considered in MS patients, but not in psoriasis patients. Embryotox recommends close monitoring of the infant by the mother and regular pediatrician follow-up.

Patent dispute and further developments

Currently, the only dimethyl fumarate-containing medications available in Germany are Biogen's MS drug Tecfidara and Almirall Hermal's psoriasis medication Skilarence. In December 2024, Biogen announced that it would initially discontinue distribution of the psoriasis medications Fumaderm® and Fumaderm. They were finally discontinued on April 15, 2025. In addition to dimethyl fumarate, Fumaderm also contained ethyl hydrogen fumarate. It had been on the market since the 1990s.

Skilarence is considered a further development and was introduced in 2017. Even then, there was speculation about Fumaderm being withdrawn from the market. Skilarence is actually cheaper, and laboratory tests are recommended only every three months, not every month as with Fumaderm.

A patent dispute is raging over Tecfidera. The ABDA (German Association of German Pharmaceutical Manufacturers) item database contains a number of generics, but they are listed as "out of distribution" and "not marketable." Some were launched in 2022, but court decisions supported Biogen's patent claim. After some back and forth , marketing protection for Tecfidera in the EU ended in February 2025. When contacted by the Pharmazeutische Zeitung, the pharmaceutical association Pro Generika was unable to provide information on whether and when any generics would be (re)available.

In early 2022, Biogen launched diroximel fumarate (Vumerity®), a new fumaric acid treatment for MS. It is considered a next-generation fumarate with improved gastrointestinal tolerability . Like dimethyl fumarate, it is a prodrug; the active main metabolite, monomethyl fumarate, is identical.