Why is Lasix (furosemide) given to patients on dialysis?

Furosemide Use in Dialysis Patients

Furosemide is indicated for dialysis patients primarily to manage residual fluid overload and maintain residual renal function, despite its limited efficacy in end-stage renal disease.

Rationale for Furosemide in Dialysis Patients

Dialysis patients may still benefit from furosemide therapy for several key reasons:

1. Management of Volume Overload

   • In patients with residual kidney function, furosemide can help manage fluid overload between dialysis sessions 1
   • The KDIGO guidelines suggest using diuretics for volume overload management in AKI patients, which can be extrapolated to dialysis patients with residual function 1

2. Preservation of Residual Renal Function

   • While evidence is limited, maintaining residual diuresis is associated with improved outcomes in dialysis patients
   • Even small amounts of residual function can contribute to better volume control and quality of life

3. Dosing Considerations

   • Higher doses are typically required due to reduced drug delivery to the site of action 2
   • Studies have used doses ranging from 250-2000 mg daily in hemodialysis patients 3
   • Even smaller doses (40 mg) have shown benefit in doubling urine output in dialysis patients with residual function 4

Clinical Evidence

Research shows variable efficacy of furosemide in dialysis patients:

• A study of high-dose furosemide (1000 mg twice daily) in hemodialysis patients demonstrated a 109% increase in 24-hour urine volume 3
• Another study showed that even 40 mg of furosemide could double urine output (1142 ml/24h vs 453 ml/24h) in hemodialysis patients with residual function 4
• In peritoneal dialysis patients, furosemide did not significantly improve urine volume or preserve residual renal function, but fewer patients became anuric at one year (5% vs 22%) 5

Practical Approach to Furosemide Use in Dialysis

1. Patient Selection

   • Only use in patients with documented residual urine output
   • Consider in patients with persistent volume overload despite adequate dialysis

2. Dosing Strategy

   • Start with higher doses than in non-dialysis patients (typically 80-160 mg daily)
   • May require doses up to 1000 mg daily in some patients 3
   • Titrate based on clinical response (urine output, weight, symptoms)

3. Monitoring

   • Track urine output response
   • Monitor for electrolyte abnormalities, particularly potassium and sodium
   • Assess for symptoms of volume depletion or ototoxicity with very high doses

Cautions and Limitations

• Furosemide should not be used to prevent AKI (1B recommendation) 1
• Limited efficacy in patients without residual renal function
• Risk of ototoxicity with very high doses, though this was not observed even with doses up to 1000 mg daily in one study 3
• May need to be discontinued if serum sodium falls below 125 mmol/L 2

Conclusion

While furosemide has limitations in dialysis patients, it remains a useful adjunctive therapy for those with residual renal function and persistent volume overload. The decision to use furosemide should be based on the presence of residual urine output and clinical evidence of volume overload that persists despite adequate dialysis.