Medicine & USMLE


  1. Amphotericin B
  2. Nystatin
  3. Flucytosine
  4. Azoles
  5. Terbinafine
  6. Echinocandins
  7. Griseofulvin


Nystatin is an antifungal drug used to treat candida infections. Nystatin binds to ergosterol, which causes holes to form in fungal membranes. Nystatin is only used topically and is too toxic to treat systemic fungal infections. Nystatin can be formulated as a cream or lotion applied to candida infections of the skin, such as with diaper rash candidiasis, or as an oral solution to be swished and swallowed to treat oral candidiasis. Since Nystatin is not absorbed in the intestines or through the skin, few side effects are seen.

Key Points

  • Nystatin
    • Mechanism
      • Binds ergosterol to form holes in fungal membranes
        • Ergosterol is unique to fungal membranes
        • Membrane holes, or pores, allow leakage of electrolytes that cause fungal cell lysis
    • Clinical Use
      • Topical use only
        • Too toxic for systemic use
        • Candidiasis
          • Swish and swallow for oral thrush
          • Topical for diaper rash/vaginal candidiasis
      • Used in laboratory settings to inhibit fungal growth (to isolate bacteria)
        • E.g. found in Thayer-Martin medium to inhibit yeast to isolate Neisseria spp.
    • Adverse Effects
      • Skin irritation or hypersensitivity