Flucytosine is an antifungal indicated only to treat severe infections throughout the body caused by susceptible strains of Candida or Cryptococcus. A fluorinated cytosine analog that is used as an antifungal agent.
- Mechanism
- Curator reviewed
Although the exact mode of action is unknown, it has been proposed that flucytosine acts directly on fungal organisms by competitive inhibition of purine and pyrimidine uptake and indirectly by intracellular metabolism to 5-fluorouracil. Flucytosine enters the fungal cell via cytosine permease; thus, flucytosine is metabolized to 5-fluorouracil within fungal organisms. The 5-fluorouracil is extensively incorporated into fungal RNA and inhibits synthesis of both DNA and RNA. The result is unbalanced growth and death of the fungal organism. It also appears to be an inhibitor of fungal thymidylate synthase.
- Primary indication
- For the treatment (in combination with amphotericin B) of serious infections caused by susceptible strains of Candida (septicemia, endocarditis and urinary system infections) and/or Cryptococcus (meningitis and pulmonary infections).Curator reviewed · 9 structured indications
- Formula / weight
- C4H4FN3O · 129.0925 g/mol (avg)
- First approval
- United States, 1971
- Also known as
- 5-FC · 5-Fluorocystosine · 5-Fluorocytosine · 5FC
- Code names
- DB107-Fc · NSC-103805 · RO 2-9915 · Toca FC
- Brand names
Resolves to
XRECTZIEBJDKEO-UHFFFAOYSA-NSMILESNC1=C(F)C=NC(=O)N1What you can answer from here — as of September 23, 2026
Which drugs share a target with Flucytosine, and which of those have an active Phase 3 trial?
Create a free account or log in to explore the full data card.
Create Account