Trexonate is a brand name for Methotrexate, a potent medication used in the treatment of various cancers, autoimmune diseases, and some skin conditions. It works as an antimetabolite by inhibiting the enzyme dihydrofolate reductase, which is essential for DNA, RNA, and protein synthesis. Methotrexate is especially effective against rapidly dividing cells, like cancer cells, and inflammatory cells in autoimmune diseases.