antibioticsbooks

Polyenes
27
Agents: amphotericin B, lipid formulations of
amphotericin B, nystatin (topical)
For many years, amphotericin B deoxycholate was
the standard of care for many systemic fungal infections,
for both its broad antifungal spectrum and
a lack of available alternatives. Polyenes work by
binding to ergosterol in the cell membrane of fungi,
disrupting its function. Amphotericin B is notable
for its toxicities, principally nephrotoxicity and
infusion-related reactions. To attenuate these toxicities,
three lipid forms were developed: amphotericin
B colloidal dispersion (ABCD), amphotericin B lipid
complex, and liposomal amphotericin B (LAmB).
Amphotericin B formulations have seen considerably
less use since the introduction of the
echinocandins and broad-spectrum azoles, but
they still have utility. Activity against yeasts and
many molds, proven efficacy in understudied disease
states, and a long history of use help maintain
their place in the antifungal armamentarium.
Mechanism of Action
Polyenes such as amphotericin B bind to ergosterol
in the fungal cell membrane, forming pores in the
membrane and leading to the leakage of cell contents
with eventual cell death.