oteracil potassium

Oteracil potassium is a small molecule enzyme inhibitor used as an adjunct in antineoplastic therapy, primarily to reduce the gastrointestinal toxicity associated with fluoropyrimidine-based chemotherapy. It is most commonly included as a component of combination oral chemotherapeutic regimens such as Teysuno (also known as S‑1), which contains tegafur (a prodrug of 5-fluorouracil), gimeracil, and oteracil potassium. Oteracil acts locally in the gut due to its low permeability and inhibits orotate phosphoribosyltransferase (OPRT), thereby reducing phosphorylation and activation of 5-fluorouracil in normal gastrointestinal mucosa. This selective inhibition helps protect healthy tissue from cytotoxic effects while allowing systemic anticancer activity[1][2][4][6]. Oteracil-containing combinations are approved for use in advanced gastric cancer, metastatic colorectal cancer, and are being investigated for other solid tumors[7][8].

Brand names

Teysuno

Other names

oteraciloteracil potassiumoxonateoxonic acid5-azaorotic acidallantoxanic acid