Lipid formulations of amphotericin B

Lipid formulations of amphotericin B have demonstrated reduced toxicity compared with conventional amphotericin B desoxycholate, allowing higher daily dosages. Three preparations with entirely different pharmacokinetic properties are currently approved in several countriesamphotericin B lipid complex (Abelcet), liposomal amphotericin B (AmBisome) and amphotericin B colloidal dispersion (Amphocil). All three lipid formulations of amphotericin B share a decreased nephrotoxicity even at dosages of 5 mg/kg. These drugs may therefore be given successfully in patients intolerant to conventional amphotericin B, although the rates of acute infusion-related reactions may differ between them. Although several animal studies showed a higher therapeutic index, high dosages were needed for treatment to be effective. It is unclear whether and at what dose these formulations would have a better efficacy than amphotericin B in clinical use. In-vitro studies, animal experiments and some clinical data suggest that one should avoid low dosages (1 mg/kg) of the current lipid formulations in the initial treatment of acute fulminant fungal infections, because the efficacy may be inferior compared with equal dosages of conventional amphotericin B. A final judgement of the clinical efficacy and relative total cost of treatment with each individual formulation can only be made by direct comparative, clinical and pharmacoeconomic studies.