Polyenes: amphotericin b
Amphotericin B products are the only polyenes currently available for systemic treatment of fungal infections. Nystatin, another polyene, is only available topically. A liposomal formulation of nystatin is in clinical development for treatment of systemic fungal infections containing invasive aspergillosis.
Polyenes act by binding to ergosterol in the fungal cell membrane, leading to loss of membrane integrity and leakage of cell contents. Conventional amphotericin B and the newer lipid-based formulations have the similar spectrum of activity and are active against most patho- genic fungi and some protozoa. Exceptions include Aspergillus ter- reus, Fusarium spp., Pseudallescheria boydii and some strains of Candida lusitaniae. Amphotericin is used for treatment of many fungal disorders including aspergillosis, blastomycosis, candidiasis, coccidioidomycosis, cryptococcosis (containing meningitis), histoplasmosis, paracoccidioidomycosis, sporotrichosis and zygomycosis. It is also used as empiric therapy in febrile neutropenic patients.