5-Fluorocytosine: An Oral Antifungal Compound

Abstract

5-Fluorocytosine, an antifungal drug with potential chemotherapeutic value, was evaluated to determine its in vitro activity against recently isolated fungal strains and was used to treat 17 patients with proved fungal infections. Ninety-two percent of Candida albicans strains, 90% of other Candida species, 83% of Torulopsis glabrata strains, and 28% of strains of Aspergillus species were inhibited by 1.95 µg/ml or less. Therapy with 5-fluorocytosine was usually successful in abdominal infections and persistent fungemia if abscesses and fistulas were drained. Candida and torulopsis pyelonephritides were almost always refractory to 5-fluorocytosine therapy; most patients with these diseases had far-advanced disease and intrarenal abscesses. Two patients with cryptococcal meningitis were not cured with 5-fluorocytosine therapy but had probably received inadequate doses. Other fungal infections responded variably. Two patients had reversible hepatotoxicity related to 5-fluorocytosine therapy. 5-Fluorocytosine may prove to be an effective alternative drug in the treatment of cryptococcus, candida, and torulopsis infections.