Tegafur is an antineoplastic (chemotherapy) agent that belongs to the fluoropyrimidine class and works as a prodrug of 5-fluorouracil (5-FU), meaning it is metabolized in the body to produce the active cancer-fighting compound that inhibits DNA synthesis in rapidly dividing cells. It was first developed in Japan in the 1970s as part of efforts to improve the effectiveness and tolerability of 5-FU-based chemotherapy by enabling oral administration and more sustained drug exposure. Tegafur is often used in combination formulations such as tegafur-uracil (UFT) or tegafur combined with modulators like gimeracil and oteracil (e.g., S-1), which enhance its anticancer activity and reduce gastrointestinal toxicity. Over time, it has become widely used in the treatment of gastrointestinal cancers, particularly gastric and colorectal cancers, especially in East Asian countries where it was first introduced and clinically developed.
