Methotrexate administered weekly in low doses is a mainstay in the therapy of rheumatoid
arthritis. Although originally developed as a folate antagonist for the treatment of cancer, its
mechanism of action in the therapy of rheumatoid arthritis remains less clear. Several
mechanisms have been proposed including inhibition of T cell proliferation via its effects on
purine and pyrimidine metabolism, inhibition of transmethylation reactions required for the
prevention of T cell cytotoxicity, interference with glutathione metabolism leading to …