Does furosemide (Lasix) improve serum creatinine levels and renal function in patients with cardiorenal syndrome?

From the Guidelines

Lasix (furosemide) does not improve creatinine levels or kidney function in cardiorenal syndrome, and its use may even lead to a temporary worsening of creatinine levels due to reduced kidney perfusion. The primary role of Lasix in cardiorenal syndrome is to manage fluid overload symptoms by increasing urine output, which helps relieve congestion, reduce edema, and improve breathing difficulties 1. The typical dosing ranges from 20-80 mg intravenously or orally, depending on the severity of fluid overload and the patient's response.

Key Considerations

• Managing fluid status is crucial in cardiorenal syndrome, but the underlying kidney dysfunction requires a comprehensive approach, including optimizing cardiac output, maintaining adequate blood pressure, avoiding nephrotoxic medications, and carefully balancing diuresis to avoid excessive dehydration 1.
• The goal of Lasix therapy in this setting is symptom management rather than improving kidney function metrics like creatinine.
• Kidney function in cardiorenal syndrome typically improves only when cardiac function improves, as the two systems are interdependent.
• The use of loop diuretics, such as Lasix, is associated with a dose-dependent decline in eGFR, and higher doses can cause more rapid decline in renal function 1.
• Monitoring of renal function is essential when using diuretics, especially in patients with pre-existing kidney dysfunction, to prevent further decline in renal function and potential adverse outcomes 1.

Clinical Implications

• Clinicians should be cautious when using Lasix in patients with cardiorenal syndrome and closely monitor renal function to avoid exacerbating kidney dysfunction.
• A comprehensive approach to managing cardiorenal syndrome, including optimizing cardiac function, maintaining adequate blood pressure, and avoiding nephrotoxic medications, is essential to improve patient outcomes.
• The use of Lasix should be tailored to the individual patient's needs, with careful consideration of the potential risks and benefits, and regular monitoring of renal function to minimize adverse effects 1.

From the Research

Cardiorenal Syndrome and Lasix Treatment

• The treatment of patients with acute heart failure (AHF) and cardiorenal syndrome type 1 (CRS-1) is not well-defined, with arterial hypoperfusion and venous congestion playing a crucial role in the pathophysiology of CRS-1 2.
• The use of loop diuretics, such as furosemide (Lasix), is a cornerstone of heart failure management, but diuretic treatment remains largely empirical, with little evidence available to guide decisions 3.
• A systematic review and meta-analysis found that the simultaneous use of hypertonic saline and IV furosemide (HSS+Fx) was associated with decreased serum creatinine levels compared to IV furosemide alone (Fx) in patients with fluid overload 4.
• The pathophysiology of cardiorenal syndrome involves the interdependence of the heart and kidneys, with dysfunction in one organ causing dysfunction in the other, and volume overload and congestion being hallmarks of heart failure 3, 5.

Effects of Lasix on Creatinine and Kidney Function

• The study by 4 found that HSS+Fx was associated with a decrease in serum creatinine levels (mean difference, -0.46 mg/dL; 95% CI, -0.51 to -0.41; p < 0.05) compared to Fx in patients with fluid overload.
• However, the optimal treatment strategy for cardiorenal syndrome, including the use of Lasix, is still not well-defined and requires further research 2, 3, 5.
• The use of diuretics, including Lasix, in patients with cardiorenal syndrome should be guided by the individual patient's response and clinical status, with careful monitoring of kidney function and electrolyte levels 3, 5.