antifolate

:  a drug (such as methotrexate, pyrimethamine, or sulfamethoxazole) that interferes with folate function especially by inhibiting the action of dihydrofolate reductase and that is used chiefly as an anticancer, antibacterial, and antimalarial agent Folinic acid has been shown to be effective in preventing toxic reactions caused by antifolates while not reducing their therapeutic activity as antimalarial agents.—Elliott K. Main et al., The Journal of the American Medical Association, 17 June 1983 The two drugs most widely used against malaria, particularly for prophylaxis, are chloroquine and the anti-folate pyrimethamine.—F.E.G. Cox, Nature, 17 Jan. 1991