A substance that makes tumor cells more sensitive to radiation therapy and is being studied in the treatment of cancer. It belongs to the families of drugs called cytidine deaminase inhibitors, multidrug resistance modulators, and radiosensitizers.

A synthetic pyrimidine nucleoside analogue with biomodulating activity. Tetrahydrouridine increases the efficacy of the radiosensitizer cytochlor (5-chloro-2'-deoxycytidine) by inhibiting the enzyme deoxycytidine monophosphate (dCMP) deaminase and preventing the premature deamination of the cytochlor metabolite 5-chloro-2'-deoxycytidine monophosphate (CldCMP) to 5-chloro-2'-deoxyuridine monophosphate (CldUMP); in turn, this increases tumor concentrations of CldUMP which is then further anabolized and incorporated selectively into tumor DNA as CldU (5-chloro-2'-deoxyuridine). (NCI04)

An inhibitor of nucleotide metabolism.