Preferred Label : Tegafur-Gimeracil-Oteracil Potassium-Leucovorin Calcium Oral Formulation;
NCIt definition : An orally bioavailable granular formulation composed of the fluoropyrimidine antagonist
tegafur combined with two modulators of 5-fluorouracil (5-FU) activity, gimeracil
and oteracil potassium, and the folic acid derivative leucovorin calcium, with potential
antineoplastic activity. Tegafur is a prodrug of 5-fluorouracil (5-FU), an antimetabolite
that is further metabolized to 5-fluoro-2'-deoxyuridine monophosphate (FdUMP) and
5-fluorouridine triphosphate (FUTP). FdUMP inhibits thymidylate synthase, DNA synthesis
and cell division; FUTP competes with uridine triphosphate (UTP), thus inhibiting
RNA and protein synthesis. Gimeracil is a reversible inhibitor of dihydropyrimidine
dehydrogenase (DPD), the liver enzyme responsible for rapid catabolism of 5-FU into
inactive metabolites. Oteracil potassium preferentially localizes in the gut and inhibits
the enzyme orotate phosphoribosyl-transferase (OPRT), which converts tegafur to 5-FU.
This decreases the amount of 5-FU in the gut and prevents activated 5-FU-related gastrointestinal
(GI) toxicity. Leucovorin calcium, an active metabolite of folic acid, counteracts
the toxic effects of 5-FU, thereby 'rescuing' the patient while permitting the antitumor
activity of 5-FU.;
Molecule name : TAS-118;
Origin ID : C120099;
UMLS CUI : C3897369;
Semantic type(s)
- chemical_or_drug_has_mechanism_of_action
- concept_is_in_subset
