trimetrexate

noun

tri·​me·​trex·​ate ˌtrī-mi-ˈtrek-ˌsāt 

: a toxic drug structurally related to methotrexate that is administered in the form of its glucuronate C₁₉H₂₃N₅O₃·C₆H₁₀O₇ with concomitant administration of leucovorin to reduce toxicity and is used especially in the treatment of Pneumocystis carinii pneumonia and certain carcinomas