What is the mechanism of action of flucytosine?

Flucytosine's mechanism of action is primarily based on its conversion into 5-fluorouracil within fungal cells. Once inside the fungal cell, flucytosine undergoes metabolic conversion to 5-fluorouracil, which is an antimetabolite that mimics the structure of uracil. This active form then interferes with nucleic acid synthesis, specifically by inhibiting thymidylate synthase, a key enzyme in the production of DNA and RNA. This disruption hinders the synthesis of nucleic acids, ultimately leading to impaired fungal growth and, in many cases, cell death.

Understanding this mechanism is crucial for comprehending how flucytosine functions alongside other antifungal agents, as it targets fungi's ability to replicate and sustain their metabolic processes. By converting to 5-fluorouracil and subsequently disrupting the nucleic acid production pathway, flucytosine effectively inhibits fungal proliferation.