Nephrotoxicity of Liposomal Amphotericin B
Introduction to Nephrotoxicity
- Liposomal amphotericin B is significantly less nephrotoxic than conventional amphotericin B deoxycholate, though approximately 19-50% of patients still experience some degree of renal injury during treatment 1, 2, 3
Comparative Nephrotoxicity Profile
- In recent outpatient therapy studies, approximately 50% of patients experienced some renal injury during treatment, but adverse events were manageable with only 12% requiring readmission and treatment discontinuation in only one patient 2, 3
Mechanism of Nephrotoxicity
- Liposomal amphotericin B binds to cholesterol in mammalian cell membranes, leading to end-organ dysfunction particularly affecting the kidneys 4
- The lipid formulation reduces direct exposure of renal tubular cells to free amphotericin B, explaining the improved safety profile 1, 3
Risk Factors for Nephrotoxicity
- High doses are the primary risk factor for nephrotoxicity - doses above standard (particularly >5 mg/kg/day) significantly increase renal toxicity risk 2, 3
- Pre-existing renal impairment, diabetes mellitus, and underlying renal disease increase susceptibility 4
- Concomitant use of other nephrotoxic medications substantially amplifies nephrotoxic risk 4
- Volume depletion and advanced age are additional patient-specific risk factors 5
Prevention and Monitoring Strategies
- Hydration with 0.9% saline intravenously 30 minutes before infusion ameliorates nephrotoxicity 4
- Volume expansion with salt loading immediately prior to dosing is warranted 4
- Monitor serum creatinine and electrolytes frequently - at minimum once or twice weekly 4
- Use the lowest effective dose and shortest duration of therapy 5
Important Clinical Caveats
- Neither dialysis nor hemofiltration significantly reduces amphotericin B serum concentrations, so dose adjustment for renal replacement therapy is not required 1, 3
- Liposomal amphotericin B remains nephrotoxic enough that echinocandins are better tolerated and preferred as first-line therapy when appropriate for the fungal pathogen 6