What are the guidelines for using Amphotericin B (antifungal medication) in patients undergoing Continuous Renal Replacement Therapy (CRRT) with impaired renal function?

Amphotericin B Management During Continuous Renal Replacement Therapy

Lipid formulations of amphotericin B should be used rather than conventional amphotericin B in patients undergoing CRRT, with no dose adjustments required for liposomal amphotericin B during CRRT. 1, 2, 3

Formulation Selection

Preferred Formulation

• Lipid formulations (particularly liposomal amphotericin B) are strongly recommended over conventional amphotericin B for patients on CRRT due to:
  • Significantly reduced nephrotoxicity 1, 2
  • Similar or superior clinical efficacy 2, 4
  • Better safety profile in patients with impaired renal function 1, 2

Evidence-Based Rationale

• KDIGO guidelines specifically recommend using lipid formulations of amphotericin B rather than conventional formulations (Grade 2A recommendation) 1
• American Society of Transplantation recommends lipid formulations of amphotericin B for patients with impaired renal function 1
• Infectious Diseases Society of America guidelines support using lipid formulations over conventional amphotericin B when equal therapeutic efficacy can be assumed (Grade 1A recommendation) 1

Dosing Considerations During CRRT

Dose Adjustments

• No dose adjustments are required for liposomal amphotericin B in patients on CRRT 3
• A nationwide observational study demonstrated that patients on CRRT can receive the same:
  • Average daily dose
  • Cumulative dose
  • Treatment duration
  • Dosing interval as patients with normal renal function 3

Monitoring Recommendations

• Monitor renal function frequently during therapy 5
• Regular monitoring of:
  • Liver function
  • Serum electrolytes (particularly magnesium and potassium)
  • Complete blood counts
  • Hemoglobin concentrations 5

Special Considerations for CRRT Patients

Drug Interactions

• Use with extreme caution when combined with other nephrotoxic medications:
  • Aminoglycosides
  • Cyclosporine
  • Pentamidine 5
  • Vancomycin 1

Potential Complications

• Despite reduced nephrotoxicity with lipid formulations, approximately 50% of patients may still experience some degree of renal injury 2
• Be aware of potential interference with ECMO circuits when using liposomal amphotericin B in patients on both ECMO and CRRT 6

Practical Management Tips

• Hydration and sodium repletion prior to amphotericin B administration may further reduce nephrotoxicity risk 5
• Supplemental alkali medication may decrease renal tubular acidosis complications 5
• Monitor for infusion-related reactions (fever, chills, hypotension) which are common 1-3 hours after starting infusion 5
• Avoid rapid intravenous infusion as it has been associated with hypotension, hypokalemia, arrhythmias, and shock 5

Conclusion

When treating fungal infections in patients on CRRT, lipid formulations of amphotericin B (particularly liposomal amphotericin B) should be used without dose adjustment. This approach maintains efficacy while minimizing additional nephrotoxicity in this already vulnerable population.