Flucytosine (5-FC)

Flucytosine a fluorinated pyrimidine analogue, is a synthetic antimycotic drug. It is structurally related to the cytostatic fluorouracil and to floxuridine. It is available in oral and in some countries also in injectable form. Flucytosine is active in vitro as well as in vivo against some strains of Candida and Cryptococcus. Limited studies demonstrate that flucytosine may be of value against infections with Sporothrix, Aspergillus, Cladosporium, Exophila, and Phialophora. Resistance is quite commonly seen as well in treatment-naive patients and under current treatment with flucytosine. In different strains of Candida resistance has been noted to occur in 1 to 50% of all specimens obtained from patients. Flucytosine is well absorbed (75 to 90%) from the gastrointestinal tract. Oral flucytosine is indicated for the treatment of serious infections caused by susceptible strains of Candida or Cryptococcus neoformans.