The use of lipid formulations of amphotericin B for systemic fungal infections.

Despite its considerable toxicity, amphotericin B (AmB) remains the 'golden standard' in the treatment of many systemic fungal infections. To reduce this toxicity, with the aim of increasing its therapeutic index, AmB can be encapsulated into liposomes or bound to lipid carriers. Following promising clinical results with investigational formulations, three industrial compounds are available at this moment: Abelcet (Amphotericin B Lipid Complex, ABLC), Amphocil (Amphotericin B Colloidal Dispersion) and AmBisome. These three formulations differ significantly in composition and pharmacokinetics. All three compounds share a considerable reduction of nephrotoxicity, but the number of acute reactions differ among these compounds, Amphocil showing the highest and AmBisome the lowest rate. Increased therapeutic indexes for all three formulations were shown only in some of the animal models for several fungal infections. Four recent clinical trials comparing these formulations with AmB demonstrated their clinical efficacy but failed to clearly show an increased therapeutic index. Therefore these compounds can be recommended in cases of intolerance to or failure on AmB therapy. The optimal therapeutic dosages have not been established, but dosages as low as 1 mg/kg should probably be avoided in the initial treatment of fulminant fungal infections, since efficacy may be inferior to equal dosages of conventional AmB.