ABSTRACT
INTRODUCTION Originally developed as a treatment for leukemia, flucytosine (5-fluorocytosine; 5FC) is an antifungal agent with a restricted role in present-day therapy. Its use as a monotherapy is significantly limited, primarily due to concerns regarding both primary and secondary flucytosine resistance. In contrast, combination therapy of flucytosine with amphotericin B has been proven to improve treatment outcomes in patients with cryptococcal meningitis when used as the initial part of therapy (1-5). Its role in combination with azole antifungals for the treatment of disseminated cryptococcal infections is less clear. In addition to concerns regarding resistance, flucytosine use is also limited by toxicities (hematologic and gastrointestinal) and the lack of a parenteral preparation in the United States. Therapeutic drug monitoring and dose adjustment in patients with renal insufficiency should be employed in an attempt to optimize therapy and reduce the potential for serum concentration-related side effects.
