Should Lasix (Furosemide) be avoided in patients with impaired renal function?

From the Guidelines

Lasix (Furosemide) should be used with caution in patients with impaired renal function.

Key Considerations

• The use of loop diuretics like furosemide in patients with impaired renal function requires careful consideration, as these patients may be more susceptible to the adverse effects of diuretics, including worsening renal function 1.
• The response to diuretics is dependent on renal function, and patients with significant impairment of renal function or perfusion may become unresponsive to high doses of diuretic drugs 1.
• The dose of furosemide should be adjusted according to renal function, and the total dose should remain below certain limits to avoid adverse effects 1.
• Monitoring of renal function is crucial when using diuretics in patients with impaired renal function, and the dose should be adjusted accordingly to avoid worsening renal function 1.

Dosage and Administration

• The recommended initial dose of furosemide is a bolus of 20–40 mg i.v., and the dose may be increased according to renal function and a history of chronic oral diuretic use 1.
• The total furosemide dose should remain below 100 mg in the first 6 hours and 240 mg during the first 24 hours 1.
• Continuous infusion may be considered after the initial starting dose, and the dose should be adjusted to maintain an active diuresis and sustain the loss of weight 1.

Potential Risks and Benefits

• The use of diuretics in patients with impaired renal function may be associated with worsening renal function, and careful monitoring is required to avoid this adverse effect 1.
• However, diuretics are essential for the treatment of fluid retention in patients with heart failure, and the benefits of diuretic therapy may outweigh the risks in patients with impaired renal function 1.

From the FDA Drug Label

In patients at high risk for radiocontrast nephropathy Furosemide tablets can lead to a higher incidence of deterioration in renal function after receiving radiocontrast compared to high-risk patients who received only intravenous hydration prior to receiving radiocontrast. Reversible elevations of BUN may occur and are associated with dehydration, which should be avoided, particularly in patients with renal insufficiency

Furosemide (Lasix) should be used with caution in patients with impaired renal function. The drug label warns that furosemide can lead to a higher incidence of deterioration in renal function, particularly in patients at high risk for radiocontrast nephropathy. Additionally, reversible elevations of BUN may occur, which are associated with dehydration and should be avoided, especially in patients with renal insufficiency 2. It is essential to monitor renal function and adjust the dosage or discontinue the drug if necessary to prevent further renal impairment.

From the Research

Impaired Renal Function and Furosemide Use

• Furosemide, a loop diuretic, is frequently used in patients with acute decompensated heart failure and acute kidney injury, but its use in patients with impaired renal function is uncertain 3, 4.
• Studies have shown that the severity of acute kidney injury has a significant effect on the diuretic response to furosemide, and a good 'urinary response' may be considered as a 'proxy' for having some residual renal function 4.
• In patients with end-stage chronic renal failure, furosemide has been shown to decrease weight gain between dialyses and increase sodium excretion rate, but it has no effect on blood pressure, creatinine clearance, and urinary excretion of potassium and nitrogen 5.

Pharmacokinetics and Elimination of Furosemide

• The plasma half-life of furosemide is prolonged in patients with renal failure, and the plasma clearance of furosemide decreases proportionally with decreasing creatinine clearance 6.
• The elimination rate of furosemide metabolites is decreased in patients with renal failure, and the main route of excretion of label is in the feces 6.
• Recent studies suggest that the diuretic response to furosemide is expressed by a steep dose-response curve positively correlated with renal function, but pharmacodynamic limitations occur when creatinine clearance is <20 ml/min or urine output is <500 ml/12 h 7.

Clinical Implications

• The use of furosemide in patients with impaired renal function should be cautious, as it may not be effective in reducing mortality or improving renal function 3, 4.
• The diuretic response to furosemide may be used as a functional marker of acute kidney injury in ICU patients, and a continuous infusion of furosemide may be superior to a bolus dose in achieving a diuretic response 7.
• However, validation studies are still needed to support the use of continuous infusion as a stress test to assess glomerular and tubular functions 7.