tegafur + gimeracil + oteracil potassium

**Tegafur + gimeracil + oteracil potassium** is an oral fixed-dose fluoropyrimidine anticancer combination developed by Taiho Pharmaceutical and widely known as S-1. It combines tegafur, a prodrug converted to 5-fluorouracil; gimeracil, a dihydropyrimidine dehydrogenase inhibitor that prolongs systemic 5-fluorouracil exposure; and oteracil potassium, an inhibitor of orotate phosphoribosyltransferase in intestinal mucosa that reduces gastrointestinal activation and toxicity. The resulting 5-fluorouracil activity primarily inhibits thymidylate synthase and disrupts RNA and DNA synthesis. It is marketed in multiple regions, including as TS-1, TS-ONE, and Teysuno, for solid tumors including gastric, colorectal, pancreatic, biliary tract, non-small cell lung, head and neck, and breast cancers.

Brand names

Teysuno

Other names

tegafur/gimeracil/oteraciltegafur-gimeracil-oteracil potassiumtegafur, gimeracil, and oteracil potassium