Gimeracil (103766-25-2) is a dihydropyrimidine dehydrogenase (DPD) inhibitor.  DPD is involved in the degradation of pyrimidine-based chemotherapeutic drugs such as 5-fluorouracil (5-FU).  Gimeracil is used along with 5-FU or Tegafur to prolong circulating concentrations of the drugs.^1,2  Gimeracil has also been shown to act as a radiosensitizer via inhibition of homologous recombination in the repair of DNA double strand breaks.³

References/Citations

1) Diasio (1999) Clinical implications of dihydropyrimidine dehydrogenase inhibition; Oncology(Williston Park), 13 17
2) Kobayakawa and Kojima (2011), Tegafur/giimeracil/oteracil (S-1) approved for the treatment of advanced gastric cancer in adults when given in combination with cisplatin: a review comparing it with other fluoropyrimidine-based therapies; Onco. Targets Ther., 4 193
3) Sakata et al. (2011), Gimeracil, an inhibitor of dihydropyrimidine dehydrogenase, inhibits the early step in homologous recombination; Cancer Sci., 102 1712