Orange-yellow crystalline powder. It is an antimetabolite and antifolate drug used in cancer treatment and autoimmune diseases.
Methotrexate (MTX), also known as amethopterin, is an antimetabolite and antifolate drug with the chemical formula C20H22N8O5 and molecular weight of 454.44 g/mol. It acts as a potent inhibitor of dihydrofolate reductase (DHFR), an enzyme critical for folate metabolism and DNA synthesis. By blocking this enzyme, methotrexate disrupts DNA synthesis and cellular replication, making it effective against rapidly dividing cancer cells. Originally developed as a chemotherapy agent, it is now also widely used for autoimmune diseases due to its immunosuppressive and anti-inflammatory properties.