RECENT animal experiments1-4 support our earlier in vitro work on the synergistic action of amphotericin B and second agents against a variety of fungi.5-9 Before these results lead to the indiscriminate use of amphotericin B and flucytosine for the treatment of all fungal infections in human beings, we would like to review some old and recent information, which might encourage some circumspection in the use of combination therapy.
Amphotericin B is a polyene macrolide that binds to sterols in eukaryotic cell membranes.10 It is the only polyene antibiotic that is sufficiently nontoxic to be useful itself in the treatment of systemic fungal infections. The relative specificity of amphotericin B for fungi is likely due to its greater avidity for ergosterol, the principal sterol in fungal cell membranes, than cholesterol, the principal sterol in animal cell membranes.11 Unfortunately, the specificity of amphotericin B for fungi compared to animal
Medoff G, Kobayashi GS. Amphotericin BOld Drug, New Therapy. JAMA. 1975;232(6):619–620. doi:10.1001/jama.1975.03250060015012