an orange-brown, crystalline powder, CHNO, that is a folic acid antagonist: used in medicine, esp. in treating leukemia, various tumors, psoriasis, and rheumatoid arthritis
See methotrexate in American Heritage Dictionary 4
(mĕthˌə-trĕkˈsāt)
noun
A toxic antimetabolite, C20H22N8O5, that acts as a folic acid antagonist to interfere with cellular reproduction and is used in the treatment of psoriasis, certain cancers, and certain inflammatory diseases such as rheumatoid arthritis.