Methotrexate: study card

Generic name

Methotrexate

Class

Dihydrofolate reductase inhibitor

Mechanism

Inhibits dihydrofolate reductase, interfering with tetrahydrofolate-dependent purine and thymidylate synthesis, DNA synthesis/repair and cellular replication. Its mechanism in rheumatoid arthritis and psoriasis is unknown.

Used for

Rheumatoid arthritis in adults; Severe psoriasis in adults; Acute lymphoblastic leukemia in adults and children as part of a combination-chemotherapy maintenance regimen; Polyarticular juvenile idiopathic arthritis in children; Selected adult mycosis fungoides or relapsed/refractory non-Hodgkin lymphoma regimens

Common side effects

Nausea and stomatitis; Myelosuppression; Hepatotoxicity

Boxed warning

Embryo-fetal toxicity, including fetal death; contraindicated in pregnancy for non-cancer indications and with prior severe methotrexate hypersensitivity. Serious or fatal bone marrow, gastrointestinal, liver, lung, skin and kidney toxicity can occur. Inadvertent once-daily administration has caused deaths.

Warnings

Contraindicated in pregnancy (non-cancer use); Serious infections; Pulmonary toxicity

Interactions

NSAIDs; Proton pump inhibitors; Sulfonamides

Brand questions use only name pairings verified against the linked product source. Unverified pairings are withheld from these questions; the other study content remains available.

Label date: 20260827 · For learning, not clinical decisions. US label and brand information; always consult the current source.

Source snapshot checked: 2026-10-21. The source document and selected fields were compared. The complete card has not had an independent clinical review.