methotrexate + montelukast

This is a combination of two small molecule drugs, methotrexate and montelukast. Methotrexate is an antimetabolite and antifolate agent used primarily as an antineoplastic in various cancers, as well as for autoimmune diseases such as rheumatoid arthritis and severe psoriasis. It works by inhibiting dihydrofolate reductase, leading to suppression of DNA synthesis, cell division, and inflammation. Montelukast is a leukotriene receptor antagonist indicated for asthma maintenance therapy, prevention of exercise-induced bronchoconstriction, and treatment of allergic rhinitis; it acts by selectively blocking cysteinyl leukotriene receptor type-1 (CysLT1), thereby reducing airway inflammation and bronchoconstriction. The combination has been studied in preclinical models for potential hepatoprotective effects (montelukast mitigating methotrexate-induced liver toxicity) and in clinical settings as adjuvant therapy in rheumatoid arthritis to improve disease activity scores[5][6]. There are no known direct pharmacokinetic or pharmacodynamic interactions between the two agents[1].