flucytosine

A pyrimidine compound and a fluorinated cytosine analog exhibiting antifungal activity. After penetration into the fungal cells, flucytosine is deaminated to its active metabolite 5-fluorouracil. 5-fluorouracil replaces uracil during fungal RNA synthesis, thereby inhibiting fungal protein synthesis. In addition, fluorouracil is further metabolized to 5-fluorodeoxyuridylic acid monophosphate, which inhibits thymidylate synthetase, thereby interrupting nucleotide metabolism, DNA synthesis and ultimately protein synthesis.