Uft is an anticancer medication composed of a fixed molar ration (1:4) of tegafur and uracil to be administered with calcium folinate. in the body, tegafur is converted into 5-fluorouracil (5-fu), the active antineoplastic metabolite. the mechanism of cytotoxicity of 5-fu is thought to be derived from the fact that 5-fluoro-deoxyuridine-monophosphate (fdump), the active metabolite of 5-fu, competes with deoxyuridine-monophosphate (dump), thereby inhibiting thymidylate synthase and subsequently dna synthesis. another active metabolite of 5-fu, 5-fluorouridine-triphosphate (futp) is integrated into cellular rna, inhibiting rna function. uracil, when combined with tegafur, enhances the antitumor activity of 5-fu due to higher 5-fu concentrations in the tumor tissue versus normal surrounding tissue compared with tegafur alone.calcium folinate enhances the cytotoxicity of 5-fu. the independent actions of uracil and leucovorin calcium provide for dual biomodulation of tegafur.