Dimetylfumarat Avansor: Uses, Dosage & Side Effects
An oral immunomodulatory agent for the treatment of relapsing forms of multiple sclerosis, helping to reduce relapses and slow disability progression
Dimetylfumarat Avansor (dimethyl fumarate) is an oral disease-modifying therapy used to treat relapsing forms of multiple sclerosis (MS). It belongs to the class of immunomodulatory agents and works by activating the Nrf2 antioxidant pathway and modulating immune responses to protect the central nervous system from inflammatory damage. Clinical trials have demonstrated that dimethyl fumarate significantly reduces relapse rates, slows disability progression, and decreases the formation of new brain lesions. It is taken as a gastro-resistant capsule twice daily and is available as a prescription-only medication initiated by a specialist neurologist.
Quick Facts: Dimetylfumarat Avansor
Key Takeaways
- Dimetylfumarat Avansor (dimethyl fumarate) is an oral disease-modifying therapy for relapsing multiple sclerosis that reduces relapse rates by approximately 44–53% and slows disability progression compared to placebo.
- The medication works through dual mechanisms: activating the Nrf2 antioxidant pathway to protect nerve cells and modulating the immune system to reduce inflammatory damage to the myelin sheath.
- Flushing and gastrointestinal symptoms are the most common side effects, typically most pronounced during the first month; taking capsules with food and starting at a lower dose significantly reduces these effects.
- Regular blood monitoring every 3 months is mandatory because dimethyl fumarate can cause lymphopenia (low lymphocyte counts), which in rare cases has been associated with progressive multifocal leukoencephalopathy (PML).
- Women of childbearing potential should use effective contraception during treatment, as dimethyl fumarate may cause harm to an unborn child based on animal study findings.
What Is Dimetylfumarat Avansor and What Is It Used For?
Dimetylfumarat Avansor contains the active substance dimethyl fumarate (DMF), a fumaric acid ester that has been developed as a disease-modifying therapy (DMT) for multiple sclerosis. Multiple sclerosis is a chronic autoimmune disease in which the body’s immune system mistakenly attacks the protective myelin sheath that surrounds nerve fibers in the brain and spinal cord. This inflammatory damage disrupts the normal transmission of nerve signals, leading to a wide range of neurological symptoms including fatigue, numbness, tingling, muscle weakness, visual disturbances, balance problems, and cognitive difficulties.
Dimethyl fumarate works through several complementary mechanisms of action. The primary pathway involves activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) transcriptional pathway. Nrf2 is a key regulator of the cellular antioxidant response. When activated, it promotes the expression of genes that protect cells against oxidative stress and inflammation — two processes that play a central role in the tissue damage seen in MS. By upregulating antioxidant and cytoprotective pathways, dimethyl fumarate helps shield neurons and oligodendrocytes (the cells that produce myelin) from the damaging effects of oxidative injury.
In addition to its neuroprotective properties, dimethyl fumarate exerts significant immunomodulatory effects. It shifts the balance of immune responses from the pro-inflammatory T helper 1 (Th1) and T helper 17 (Th17) pathways toward the anti-inflammatory T helper 2 (Th2) phenotype. Th1 and Th17 cells are key drivers of the autoimmune attack on myelin in MS, so reducing their activity directly addresses the underlying disease process. Dimethyl fumarate also reduces the overall number of circulating lymphocytes, particularly memory T cells and B cells that are involved in sustaining the autoimmune response.
After oral administration, dimethyl fumarate undergoes rapid pre-systemic hydrolysis by intestinal esterases to form its primary active metabolite, monomethyl fumarate (MMF). MMF is the pharmacologically active compound responsible for the therapeutic effects. It reaches peak plasma concentrations approximately 2 to 2.5 hours after dosing. Importantly, MMF is metabolized via the tricarboxylic acid (TCA or Krebs) cycle and does not involve the hepatic cytochrome P450 (CYP) enzyme system, which significantly reduces the potential for drug-drug interactions compared to many other MS therapies.
Dimetylfumarat Avansor is specifically indicated for the treatment of adult patients with relapsing-remitting multiple sclerosis (RRMS), the most common form of the disease, characterized by clearly defined episodes of new or worsening neurological symptoms (relapses) followed by periods of partial or complete recovery (remissions). It may also be used in patients with active secondary progressive multiple sclerosis (SPMS) who continue to experience relapses. The treatment is approved by the European Medicines Agency (EMA) and regulatory authorities worldwide and is considered a first-line or early treatment option for many patients with relapsing MS.
The efficacy of dimethyl fumarate was established in two large, pivotal Phase III clinical trials: DEFINE (Determination of the Efficacy and Safety of Oral Fumarate in Relapsing-Remitting MS) and CONFIRM (Comparator and an Oral Fumarate in Relapsing-Remitting Multiple Sclerosis). In these trials involving over 2,600 patients, dimethyl fumarate 240 mg twice daily reduced the annualized relapse rate by 44–53% compared to placebo, reduced the risk of 12-week confirmed disability progression by approximately 38%, and reduced new or enlarging T2-hyperintense lesions on MRI by 71–85%. Long-term extension studies have shown sustained efficacy and a favorable benefit-risk profile over more than 10 years of treatment.
What Should You Know Before Taking Dimetylfumarat Avansor?
Contraindications
There are specific situations in which Dimetylfumarat Avansor must not be used. Understanding these contraindications is essential for safe prescribing and use.
- Hypersensitivity: Do not take Dimetylfumarat Avansor if you are allergic to dimethyl fumarate or any of the other ingredients in the capsule, including the gastro-resistant coating components. Allergic reactions may include skin rash, swelling of the face, lips, tongue, or throat, and difficulty breathing.
- Concurrent use with other fumaric acid derivatives: Dimetylfumarat Avansor should not be used together with other medicinal products containing fumaric acid esters (such as those used for psoriasis), as this would result in additive immunosuppressive effects and increase the risk of serious adverse events including severe lymphopenia.
- Severe active gastrointestinal disease: Patients with severe active gastrointestinal conditions, such as active peptic ulcer disease or inflammatory bowel disease, should exercise extreme caution, as the drug can exacerbate gastrointestinal symptoms.
Warnings and Precautions
PML is a rare but serious and potentially fatal brain infection caused by the JC virus. Cases of PML have been reported in patients treated with dimethyl fumarate, particularly those with severe and prolonged lymphopenia (lymphocyte counts below 0.5 × 109/L for more than 6 months). If your lymphocyte counts remain severely low, your doctor may recommend stopping treatment. Symptoms of PML include progressive weakness on one side of the body, clumsiness, visual disturbances, confusion, personality changes, and difficulty thinking. Contact your doctor immediately if you notice any of these symptoms.
Before and during treatment with Dimetylfumarat Avansor, your doctor will assess the following:
- Lymphocyte monitoring: A complete blood count (CBC) including differential white blood cell count and lymphocyte count must be obtained before starting treatment, every 3 months during treatment, and as clinically indicated. Dimethyl fumarate can cause a sustained decrease in lymphocyte counts. Approximately 2–6% of patients develop grade 3 lymphopenia (below 0.5 × 109/L). Treatment should be interrupted if lymphocyte counts fall below 0.5 × 109/L and remain at that level for more than 6 months.
- Infections: Dimethyl fumarate may increase susceptibility to infections due to its effects on the immune system. Patients should be monitored for signs of infection during and for at least 4 weeks after discontinuation of treatment. In patients with serious or opportunistic infections, treatment suspension should be considered. Before initiating treatment, patients should be screened for latent infections including tuberculosis and hepatitis B.
- Liver function: Clinically significant cases of liver injury have been reported. Serum aminotransferase levels (ALT, AST), alkaline phosphatase, and total bilirubin should be measured before starting treatment and during treatment as clinically indicated. Patients should be instructed to report symptoms such as nausea, vomiting, abdominal pain, fatigue, anorexia, jaundice, or dark urine.
- Kidney function: Cases of Fanconi syndrome (a disorder of kidney tubular function) have been reported during treatment with dimethyl fumarate. Kidney function should be assessed before starting treatment and periodically thereafter. Symptoms may include increased thirst and urination, muscle weakness, bone pain, and unexplained metabolic abnormalities.
- Flushing: Flushing (warmth, redness, itching, or burning sensation) is very common, occurring in up to 40% of patients. It is caused by activation of prostaglandin pathways and is not an allergic reaction. Taking aspirin (325 mg) approximately 30 minutes before dosing may reduce flushing. The incidence typically decreases substantially after the first month of treatment.
- Severe skin reactions: Rare cases of anaphylaxis and angioedema have been reported. Patients should discontinue the medicine and seek immediate medical attention if symptoms of a serious allergic reaction occur.
- Herpes zoster: Serious cases of herpes zoster (shingles), including disseminated herpes zoster, herpes zoster ophthalmicus, herpes zoster meningoencephalitis, and herpes zoster meningomyelitis, have been reported. Patients experiencing signs of herpes zoster should receive appropriate antiviral treatment.
Your doctor will perform regular blood tests and clinical assessments to monitor for these potential complications throughout your treatment with Dimetylfumarat Avansor.
Pregnancy and Breastfeeding
Dimetylfumarat Avansor is generally not recommended during pregnancy. Animal studies have shown adverse developmental effects at doses higher than those used clinically, including reduced fetal weight and skeletal variations. There are limited data from the use of dimethyl fumarate in pregnant women. As a precautionary measure, women of childbearing potential should use effective contraception during treatment. If a woman becomes pregnant while taking the medication, treatment should be discontinued and the patient should be referred to a specialist for counseling regarding the risks and benefits.
It is not known whether dimethyl fumarate or its active metabolite monomethyl fumarate are excreted in human breast milk. Because many drugs are excreted in human milk and there is potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue breastfeeding or to discontinue the drug, taking into account the importance of the medicine to the mother. Discuss the best approach with your neurologist.
There is limited information on the effects of dimethyl fumarate on male fertility. Animal studies did not show adverse effects on male or female fertility at clinically relevant doses. However, if you are planning to start a family, discuss this with your neurologist before or during treatment.
Driving and Operating Machinery
No studies on the effects of dimethyl fumarate on the ability to drive and use machines have been performed. Dimethyl fumarate is not expected to significantly affect your ability to drive or operate machinery. However, as multiple sclerosis itself can affect coordination and reaction times, and some patients may experience dizziness as a side effect, you should exercise caution until you know how the medicine affects you personally.
How Does Dimetylfumarat Avansor Interact with Other Drugs?
Dimethyl fumarate has a favorable pharmacokinetic profile with regard to drug interactions. After oral administration, it is rapidly converted to its active metabolite monomethyl fumarate (MMF) by intestinal esterases. MMF is further metabolized via the tricarboxylic acid (TCA) cycle, without involvement of the cytochrome P450 (CYP) enzyme system. This means dimethyl fumarate is unlikely to affect the metabolism of other drugs processed by CYP enzymes, and drugs that inhibit or induce CYP enzymes are unlikely to affect the levels of dimethyl fumarate.
In vitro studies have shown that at therapeutically relevant concentrations, MMF and dimethyl fumarate do not inhibit or induce CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, or CYP3A4. They are also not significant substrates or inhibitors of the major drug transporters, including P-glycoprotein, BCRP, OAT1, OAT3, OATP1B1, OATP1B3, OCT1, or OCT2. This lack of CYP and transporter involvement provides a high degree of confidence that clinically significant pharmacokinetic interactions with most concomitant medications are unlikely.
Despite the low risk of pharmacokinetic interactions, there are important pharmacodynamic considerations when using dimethyl fumarate alongside other medications. The following table summarizes the key interactions that healthcare providers and patients should be aware of.
Major Interactions
| Interacting Drug | Effect | Clinical Significance |
|---|---|---|
| Other immunosuppressants (e.g., azathioprine, methotrexate, cyclosporine) | Additive immunosuppression; increased risk of severe infections and lymphopenia | Avoid concurrent use; increased PML risk |
| Other MS disease-modifying therapies (e.g., fingolimod, natalizumab, teriflunomide) | Additive or synergistic immunosuppression | Do not combine; adequate washout period required when switching |
| Other fumaric acid esters (e.g., products for psoriasis) | Increased exposure to fumaric acid derivatives and additive side effects | Contraindicated – do not use together |
| Live vaccines (e.g., MMR, varicella, yellow fever, live influenza) | Risk of uncontrolled infection from the live vaccine organism due to immunosuppression | Avoid during treatment; complete vaccinations before starting therapy |
| Nephrotoxic agents (e.g., aminoglycosides, NSAIDs at high doses, certain antivirals) | Potential additive risk of renal tubular injury (Fanconi syndrome) | Monitor kidney function closely if concurrent use is necessary |
Minor Interactions
| Interacting Drug | Effect | Clinical Significance |
|---|---|---|
| Aspirin (acetylsalicylic acid) | May reduce flushing associated with dimethyl fumarate | Beneficial interaction; 325 mg aspirin 30 min before dosing can be used as premedication |
| Oral contraceptives | No clinically significant pharmacokinetic interaction demonstrated | Can be used safely together; no dose adjustment needed |
| Inactivated vaccines | Immune response may be slightly reduced but generally adequate | Inactivated vaccines can be given during treatment; assess immune response if possible |
| Interferon beta | No pharmacokinetic interaction; overlapping immunomodulatory effects | Sequential use is acceptable with appropriate washout; concurrent use is not recommended |
When switching from another disease-modifying therapy to Dimetylfumarat Avansor, an appropriate washout period should be observed to minimize the risk of additive immunosuppression. The duration of the washout period depends on the half-life and mechanism of action of the previous therapy. For example, switching from fingolimod may require several months for lymphocyte counts to recover. Your neurologist will determine the optimal timing based on your individual clinical situation and blood test results.
What Is the Correct Dosage of Dimetylfumarat Avansor?
Dimetylfumarat Avansor treatment should be initiated and supervised by a physician experienced in the management of multiple sclerosis, typically a consultant neurologist. The dosing regimen is straightforward and designed to minimize the initial side effects that are most common during the first weeks of treatment.
Adults
Standard Adult Dosing
Starting dose (Days 1–7): 120 mg (one capsule) taken orally twice daily, approximately 12 hours apart, with food.
Maintenance dose (Day 8 onwards): 240 mg (one capsule) taken orally twice daily, approximately 12 hours apart, with food.
The gastro-resistant capsules must be swallowed whole and must not be crushed, chewed, opened, or dissolved. The gastro-resistant coating is designed to protect the active substance from the acidic environment of the stomach and to release it in the small intestine, which helps reduce gastrointestinal irritation.
Taking the capsules with food is strongly recommended. Clinical data show that administering dimethyl fumarate with a meal significantly reduces both the incidence and severity of flushing and gastrointestinal adverse events. A meal containing fat may be particularly helpful. Patients should try to take their doses at approximately the same times each day to maintain consistent blood levels of the active metabolite.
For patients who experience persistent and bothersome flushing during the initial weeks, a temporary dose reduction back to 120 mg twice daily for up to 4 weeks may be considered by the prescribing physician. However, the patient should return to the full maintenance dose of 240 mg twice daily within 4 weeks, as the therapeutic efficacy has been established at this dosage level. Long-term use of the 120 mg dose has not been shown to provide adequate disease control.
Children and Adolescents
Pediatric Use
The safety and efficacy of dimethyl fumarate in children and adolescents below 18 years of age have not been established. There are currently no data available from controlled clinical trials in this age group. Off-label use in pediatric MS patients may occur at the discretion of a specialist neurologist, typically using weight-adjusted doses or the standard adult dosing regimen in adolescents weighing over 50 kg.
Elderly Patients
Elderly Dosing
Clinical trials with dimethyl fumarate included a limited number of patients aged 55 years and above, and did not include sufficient numbers of patients aged 65 and over to determine whether they respond differently from younger patients. No dose adjustment is recommended based on age alone. However, as elderly patients may be more likely to have decreased hepatic, renal, or cardiac function, care should be taken in dose selection and monitoring.
Renal and Hepatic Impairment
No dose adjustment is required for patients with renal or hepatic impairment. Since dimethyl fumarate is metabolized via the TCA cycle rather than by the liver or kidneys, impairment of these organs is not expected to significantly affect drug clearance. However, patients with renal impairment should be monitored more closely due to the reported risk of Fanconi syndrome, and liver function should be assessed periodically in all patients.
Missed Dose
If you miss a dose of Dimetylfumarat Avansor, take it as soon as you remember. However, if it is close to the time for your next scheduled dose, skip the missed dose and take the next dose at the regular time. Do not take a double dose to make up for a missed one. It is important to maintain the twice-daily dosing schedule as consistently as possible, but missing a single dose occasionally is not expected to significantly affect the overall therapeutic benefit. If you frequently forget doses, speak with your neurologist about strategies to improve adherence.
Overdose
There is limited clinical experience with overdose of dimethyl fumarate. In the event of an overdose, the patient should be closely monitored for signs and symptoms consistent with the known side effect profile of the medicine, particularly severe flushing, gastrointestinal distress, and potential hematological effects. There is no specific antidote for dimethyl fumarate overdose. Treatment should be supportive and symptomatic. Because monomethyl fumarate has a short half-life of approximately 1 hour, symptoms from acute overdose would be expected to resolve relatively quickly. In cases of significant overdose, contact your local poison control center or emergency services.
| Patient Group | Starting Dose | Maintenance Dose | Notes |
|---|---|---|---|
| Adults | 120 mg twice daily (Days 1–7) | 240 mg twice daily | Take with food; swallow capsules whole |
| Children <18 years | Not established | Not established | Safety and efficacy not demonstrated; specialist use only |
| Elderly (≥65 years) | 120 mg twice daily (Days 1–7) | 240 mg twice daily | No dose adjustment; monitor renal and hepatic function |
| Renal impairment | Standard dosing | Standard dosing | Monitor kidney function; watch for Fanconi syndrome |
| Hepatic impairment | Standard dosing | Standard dosing | Monitor liver enzymes periodically |
What Are the Side Effects of Dimetylfumarat Avansor?
Like all medicines, Dimetylfumarat Avansor can cause side effects, although not everybody gets them. The safety profile of dimethyl fumarate has been extensively characterized in clinical trials involving thousands of patients and in post-marketing surveillance since the drug’s initial approval. The most frequently reported adverse reactions are flushing and gastrointestinal events, which are generally mild to moderate in severity and tend to diminish significantly after the first month of treatment.
In the pivotal DEFINE and CONFIRM clinical trials, the most commonly reported reasons for treatment discontinuation were gastrointestinal events (4% of patients on the 240 mg twice daily dose vs. 1% on placebo) and flushing (3% vs. less than 1%). Overall, the proportion of patients who discontinued treatment due to adverse events was approximately 16% for dimethyl fumarate versus 13% for placebo, indicating that the majority of patients tolerate the medication well with continued use.
The following side effect frequency grid summarizes the adverse reactions reported with Dimetylfumarat Avansor, categorized by their frequency of occurrence according to international conventions.
Very Common
Affects more than 1 in 10 patients
- Flushing (warmth, redness, itching, or burning sensation of the skin, particularly on the face, neck, chest, and arms)
- Diarrhea
- Nausea
- Abdominal pain (upper abdominal pain)
Common
Affects 1 in 10 to 1 in 100 patients
- Vomiting
- Dyspepsia (indigestion)
- Gastritis (inflammation of the stomach lining)
- Gastrointestinal disorder
- Burning sensation
- Hot flush
- Pruritus (itching)
- Rash, erythema (skin redness)
- Proteinuria (protein in the urine)
- Feeling of warmth
- Lymphopenia (decreased lymphocyte count)
- Leukopenia (decreased white blood cell count)
- Elevated liver transaminases (ALT, AST)
- Albumin in urine
- Ketones in urine
Uncommon
Affects 1 in 100 to 1 in 1,000 patients
- Severe lymphopenia (lymphocyte counts below 0.5 × 109/L)
- Hypersensitivity reactions
- Angioedema (swelling under the skin)
Rare
Affects fewer than 1 in 1,000 patients
- Progressive multifocal leukoencephalopathy (PML)
- Anaphylaxis (severe allergic reaction)
- Fanconi syndrome (kidney tubular dysfunction)
- Herpes zoster (shingles), including disseminated and ophthalmic forms
- Liver injury (clinically significant hepatotoxicity)
Not Known
Frequency cannot be estimated from available data
- Opportunistic infections during severe lymphopenia
- Immune reconstitution inflammatory syndrome (IRIS) after treatment discontinuation
Managing Common Side Effects
Flushing and gastrointestinal side effects can be managed with several practical strategies. Taking dimethyl fumarate with food, particularly a meal containing some fat, significantly reduces the incidence and severity of both flushing and stomach upset. Pre-medication with aspirin (325 mg, taken approximately 30 minutes before the dose) has been shown to reduce flushing symptoms. The gradual dose titration during the first week (starting at 120 mg twice daily before increasing to 240 mg twice daily) is specifically designed to reduce these initial side effects.
Patients should be reassured that flushing and gastrointestinal symptoms typically peak during the first month of treatment and decline substantially thereafter. In clinical trials, fewer than 5% of patients discontinued treatment due to these effects. Antiemetic medications or antidiarrheal agents may be used temporarily if gastrointestinal symptoms are particularly bothersome.
Contact your doctor immediately if you experience: persistent fever or signs of infection; progressive weakness, vision changes, or confusion (possible PML); severe abdominal pain, jaundice, or dark urine (possible liver injury); unusual tiredness with recurrent infections (possible severe lymphopenia); or widespread skin blistering or peeling. Regular blood monitoring is essential to detect lymphopenia early.
How Should You Store Dimetylfumarat Avansor?
Proper storage of Dimetylfumarat Avansor is important to ensure the medicine remains effective and safe throughout its shelf life. The gastro-resistant capsules are sensitive to moisture and heat, and the gastro-resistant coating can be compromised if the capsules are exposed to unfavorable conditions.
Store the capsules at a temperature not exceeding 30°C (86°F). Do not refrigerate or freeze the capsules. Keep the capsules in their original blister packaging to protect them from moisture and light. The blister packaging has been specifically designed to maintain the stability and integrity of the gastro-resistant coating. Only remove capsules from the blister pack immediately before taking them.
Do not use Dimetylfumarat Avansor after the expiry date stated on the carton and blister pack. The expiry date refers to the last day of that month. Keep this medicine out of the sight and reach of children. Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to dispose of medicines you no longer use. These measures will help to protect the environment.
If you notice any visible changes in the appearance of the capsules, such as discoloration, swelling, or damage to the coating, do not take them and consult your pharmacist. Damaged capsules may not release the active substance correctly and could cause increased gastrointestinal irritation due to breakdown of the gastro-resistant coating.
What Does Dimetylfumarat Avansor Contain?
Understanding the composition of your medicine is important, particularly if you have known allergies or sensitivities to specific pharmaceutical ingredients. Below is a summary of the active and inactive ingredients in Dimetylfumarat Avansor capsules.
Active substance: Each gastro-resistant hard capsule contains 120 mg or 240 mg of dimethyl fumarate (also known as dimethyl (E)-butenedioate). Dimethyl fumarate is a white to off-white crystalline powder. It is a methyl ester of fumaric acid, a naturally occurring substance found in certain plants and produced as an intermediate in the citric acid cycle in human metabolism.
Other ingredients (excipients): The capsule contents typically include microcrystalline cellulose, croscarmellose sodium, talc, silica colloidal anhydrous, magnesium stearate, and triethyl citrate. The gastro-resistant coating contains methacrylic acid-methyl methacrylate copolymer (providing the enteric resistance), talc, triethyl citrate, and simethicone. The capsule shell is composed of gelatin, titanium dioxide (E171), iron oxide yellow (E172), FD&C Blue No. 1 (Brilliant Blue FCF, E133), and other coloring agents depending on the capsule strength.
The 120 mg capsules are typically green and white or white/green, while the 240 mg capsules are typically green, allowing patients and healthcare providers to easily distinguish between the two strengths. The exact appearance may vary depending on the manufacturer and market authorization. Your pharmacist can confirm the appearance of the specific capsules dispensed to you.
Dimetylfumarat Avansor does not contain lactose, gluten, or any ingredients derived from animal sources other than gelatin in the capsule shell. Patients who strictly avoid gelatin (for dietary, religious, or ethical reasons) should discuss alternative formulations or products with their neurologist and pharmacist.
Frequently Asked Questions About Dimetylfumarat Avansor
Dimetylfumarat Avansor (dimethyl fumarate) is a disease-modifying therapy used to treat relapsing forms of multiple sclerosis (MS) in adults. This includes relapsing-remitting MS (RRMS), the most common form of the disease, and active secondary progressive MS. It helps reduce the frequency of relapses (flare-ups of MS symptoms), slows the progression of physical disability, and decreases the number of new or enlarging lesions in the brain visible on MRI scans. It does not cure MS but is an effective long-term treatment for managing the disease.
Dimethyl fumarate works through multiple complementary mechanisms. Its primary action involves activating the Nrf2 pathway, a key cellular defense system against oxidative stress. This protects nerve cells and the myelin sheath from inflammatory damage. Additionally, it modulates the immune system by shifting the balance away from pro-inflammatory T helper 1 (Th1) and T helper 17 (Th17) cells that attack myelin, toward anti-inflammatory T helper 2 (Th2) responses. It also reduces the overall number of certain immune cells (lymphocytes) that contribute to the autoimmune attack on the central nervous system.
Dimethyl fumarate begins affecting the immune system within weeks of starting treatment. Changes in lymphocyte counts can be observed within the first month. However, the clinical benefit in terms of reducing MS relapses develops gradually over the first several months. In clinical trials, the significant reduction in relapse rates was measured over a 2-year period. Most neurologists consider that the full therapeutic effect is established after approximately 3 to 6 months of consistent treatment. It is important to continue taking the medicine as prescribed, even if you do not notice immediate benefits, as the medication works to prevent future relapses and slow disease progression over time.
Yes, and it is strongly recommended to do so. Taking Dimetylfumarat Avansor with food significantly reduces the incidence and severity of the most common side effects: flushing and gastrointestinal discomfort. A meal containing some fat may be particularly helpful. The capsules should be swallowed whole with water or another liquid — do not crush, chew, or open the capsules, as this would destroy the gastro-resistant coating and could lead to increased stomach irritation and reduced absorption of the active substance.
Regular blood monitoring is mandatory during treatment with dimethyl fumarate. A complete blood count (CBC) with differential, including lymphocyte count, must be performed before starting treatment, every 3 months during treatment, and as clinically indicated. This is essential because the medicine can cause a sustained decrease in lymphocyte counts (lymphopenia), and severe lymphopenia has been associated with the rare but serious risk of progressive multifocal leukoencephalopathy (PML). Your doctor will also check liver function tests (ALT, AST, bilirubin) and kidney function tests before starting and periodically during treatment.
In the pivotal clinical trials, dimethyl fumarate 240 mg twice daily reduced the annualized relapse rate by 44–53% compared to placebo and by approximately 29% compared to glatiramer acetate (in the CONFIRM trial). It also significantly reduced disability progression and new MRI lesions. Dimethyl fumarate is generally considered a moderately effective oral disease-modifying therapy. It is often positioned as a first-line treatment option alongside interferon beta, glatiramer acetate, and teriflunomide. For patients with highly active MS, higher-efficacy therapies such as natalizumab, ocrelizumab, or alemtuzumab may be considered. Your neurologist will recommend the most appropriate therapy based on your disease activity, risk factors, and personal preferences.
References
- Gold R, Kappos L, Arnold DL, et al. Placebo-controlled phase 3 study of oral BG-12 for relapsing multiple sclerosis. N Engl J Med. 2012;367(12):1098-1107. doi:10.1056/NEJMoa1114287 (DEFINE trial)
- Fox RJ, Miller DH, Phillips JT, et al. Placebo-controlled phase 3 study of oral BG-12 or glatiramer in multiple sclerosis. N Engl J Med. 2012;367(12):1087-1097. doi:10.1056/NEJMoa1206328 (CONFIRM trial)
- European Medicines Agency (EMA). Tecfidera (dimethyl fumarate) – Summary of Product Characteristics (SmPC). Last updated 2025. Available at: ema.europa.eu
- U.S. Food and Drug Administration (FDA). Tecfidera (dimethyl fumarate) – Prescribing Information. Reference ID: 5111262. Available at: accessdata.fda.gov
- Linker RA, Lee DH, Ryan S, et al. Fumaric acid esters exert neuroprotective effects in neuroinflammation via activation of the Nrf2 antioxidant pathway. Brain. 2011;134(Pt 3):678-692. doi:10.1093/brain/awq386
- Gold R, Arnold DL, Bar-Or A, et al. Long-term effects of delayed-release dimethyl fumarate in multiple sclerosis: Interim analysis of ENDORSE, a randomized extension study. Mult Scler. 2017;23(2):253-265. doi:10.1177/1352458516649037
- Montalban X, Gold R, Thompson AJ, et al. ECTRIMS/EAN guideline on the pharmacological treatment of people with multiple sclerosis. Eur J Neurol. 2018;25(2):215-237. doi:10.1111/ene.13536
- Rae-Grant A, Day GS, Marrie RA, et al. Practice guideline recommendations summary: Disease-modifying therapies for adults with multiple sclerosis. Neurology. 2018;90(17):777-788. doi:10.1212/WNL.0000000000005347 (AAN Guidelines)
- World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd list, 2023. Geneva: WHO; 2023.
- Prosperini L, Pontecorvo S. Dimethyl fumarate in the management of multiple sclerosis: appropriate patient selection and special considerations. Ther Clin Risk Manag. 2016;12:339-350. doi:10.2147/TCRM.S85099
Editorial Team
Medical Content
iMedic Medical Editorial Team – Specialists in Clinical Pharmacology and Neurology
Medical Review
iMedic Medical Review Board – Independent review according to WHO, EMA, and FDA guidelines
Evidence Standard
Level 1A – Based on systematic reviews and meta-analyses of randomized controlled trials
Last Updated
January 15, 2026 – Reviewed against current EMA SmPC, FDA label, and AAN/ECTRIMS guidelines
This article follows the iMedic editorial standards for medical accuracy, transparency, and independence. All content is evidence-based and free from commercial influence. Read our editorial standards.