Name: Flucytosine (Ancobon)
Class: Antifungal
Mech.: Converted to 5-fluorouracil in fungi (enzyme not in humans). 5-fluorouracil ® phosph deoxyribose that inhibits thymidylate synth. Fungistatic.
Absorption: Well absorbed orally.
Distribution: Passes BBB (75%) ® good CSF. Aqueous humor, bronchial secretions. Poorly bound by serum proteins.
Metab.:
Excretion, t½: 1° glomerular filtration (unmetab. product). 3-4 hr ® 200 hr w/renal failure. Dose must be adjusted if renal fxn compromised.
Toxicity/S.E.s: Bone marrow depression with anemia, thrombocytopenia, leukopenia. Nausea, rashes, eosinophilisa, severe diarrhea, reversible hepatic dysfxn. Confusion, hallucinations, headache, vertigo, possibly fatal enterocolitis (esp. in comb. w/Amphoter.).
Utility: DOC for Chromomycosis. Used in comb. w/Amph for systemic Candida Albicans.
Special Features: Narrower spectrum than Amphotericin B. Resistance develops rapidly, so usu. used in comb., except to treat Chromomycosis