Flucytosine

Abstract

Flucytosine (5-fluorocytosine; 5-flucytosine; 5-FC) is one of the oldest antifungal agents in use [1]. It was initially synthesized in 1957, but was not discovered to possess significant antifungal properties until 1964, when activity against Cryptococcus neoformans and Candida species was shown [2]. Human clinical trials were initiated in the late 1960s for both cryptococcal meningitis and disseminated candidiasis [3, 4]. The rapid emergence of flucytosine resistance was observed, particularly among C. neoformans isolates, limiting its utility as single-agent therapy [5-7]. Presently, flucytosine is utilized as single-agent therapy in only a limited number of settings, including urinary candidiasis and chromoblastomycosis [8]. The seminal studies of combination therapy of flucytosine with amphotericin B for patients with cryptococcal meningitis were the first to firmly establish a role for combination antifungal therapy for a well-defined invasive fungal infection [9, 10].