5fluorodeoxycytidine

5fluorodeoxycytidine, also known as 5-fluoro-2'-deoxycytidine or FCdR, is a nucleoside analog of deoxycytidine. It is a fluorinated pyrimidine derivative. In its biological context, it can be formed from the metabolism of 5-fluorouracil (5-FU), a widely used chemotherapy drug. Once inside the cell, 5-FU can be converted into various active metabolites, including 5-fluoro-2'-deoxyuridine monophosphate (FdUMP) and 5-fluoro-2'-deoxycytidine triphosphate (FdCTP). FCdR itself is not typically administered directly as a therapeutic agent but rather arises from the in vivo processing of other drugs.

The primary mechanism of action associated with FCdR's effects, particularly in the context of chemotherapy, is related to its ability to interfere with DNA synthesis and function. FdUMP, derived from FCdR, is a potent inhibitor of thymidylate synthase, an enzyme crucial for the de novo synthesis of thymidine triphosphate, a necessary building block for DNA. Inhibition of this enzyme leads to a depletion of thymidine triphosphate, disrupting DNA replication and repair. Additionally, FdCTP can be incorporated into DNA, leading to DNA damage and cell death. These mechanisms contribute to the cytotoxic effects observed when 5-FU is administered, and by extension, the role of FCdR in these processes.