Dimethyl Fumarate + Montelukast

The combination of dimethyl fumarate (DMF) and montelukast is primarily utilized to mitigate gastrointestinal (GI) side effects associated with dimethyl fumarate treatment in patients with multiple sclerosis (MS). Dimethyl fumarate (Tecfidera) is an immunomodulator approved for treating relapsing forms of MS, but its GI side effects frequently challenge therapy adherence, potentially leading to delayed titration or discontinuation. Montelukast (Singulair), a leukotriene receptor antagonist primarily indicated for asthma, exercise-induced bronchoconstriction, and allergic rhinitis, has been repurposed for this adjunctive role. The proposed mechanism involves montelukast's effect on eosinophils, which may contribute to Tecfidera-related GI issues. This approach has been explored in studies, including the MITIGATE trial, to formally assess montelukast's role in improving dimethyl fumarate tolerability. Additionally, a 2024 retrospective study suggested that montelukast may offer an independent benefit in MS patients by significantly reducing relapse rates.