ChEBI: Flucytosine is an organofluorine compound that is cytosine that is substituted at position 5 by a fluorine. A prodrug for the antifungal 5-fluorouracil, it is used for the treatment of systemic fungal infections. It has a role as a prodrug. It is an organofluorine compound, a pyrimidone, an aminopyrimidine, a nucleoside analogue and a pyrimidine antifungal drug. It derives from a cytosine.