Lonsurf

Trifluridine is a nucleoside metabolic inhibitor, which means that it affects the DNA synthesis needed for cancer cells to divide. Tipiracil blocks the action of thymidine phosphorylase, an enzyme that is found in many solid tumors. Trifluridine is broken down by thymidine phosphorylase. By blocking trifluridine from being broken down, tipiracil increases its exposure to cancer cells, causing further cell destruction.