Antimicrobial
Flucytosine
5-FC converted to antifungal 5-FU
floo-SY-toh-seen
High-yield clue
Fungal cytosine deaminase converts flucytosine to 5-FU, which impairs fungal DNA/RNA synthesis; human cells lack this enzyme.
Overview
A pyrimidine-analog antifungal (5-FC) studied for uptake by fungal cytosine permease and conversion by cytosine deaminase to 5-fluorouracil, disrupting fungal nucleic acid synthesis.
Classification
- Antifungal pyrimidine analog
- Prodrug converted by fungal cytosine deaminase
- Yields 5-fluorouracil
- Inhibits fungal DNA/RNA synthesis
Lab & identification clues
- Fungal-selective cytosine deaminase activation concept
- Rapid monotherapy resistance vocabulary
- Bone-marrow suppression monitoring concept
Associations
- Cryptococcal and Candida study associations
- In-vitro synergy with polyene cell-membrane agents framed as a mechanism concept
- Selective toxicity from absent human cytosine deaminase
Commonly confused with
- Azoles
- Polyenes
Your notes
Original mechanism summary for microbiology study. Sources checked: CDC antimicrobial-resistance guidance, NCBI Bookshelf Medical Microbiology, and standard coursework frameworks; reviewed 2026-06. Covers class, mechanism, and resistance vocabulary only; no prescribing, dosing, or patient-specific treatment guidance.