Can diuretics, such as furosemide (Lasix), worsen Acute Kidney Injury (AKI)?

Can Diuretics Worsen AKI?

Yes, diuretics can worsen acute kidney injury (AKI) and should not be used to prevent or treat AKI itself—they are only appropriate for managing volume overload in hemodynamically stable patients. 1, 2, 3

Evidence Against Diuretic Use in AKI

Prevention and Treatment

• The KDIGO guidelines provide a Level 1B recommendation against using diuretics to prevent AKI, based on randomized controlled trials and meta-analyses demonstrating that furosemide does not prevent AKI and may actually increase mortality. 1, 2
• Diuretics should not be used to treat AKI except for managing volume overload (Level 2C recommendation). 1, 3
• The theoretical benefit of preserving renal medullary oxygenation through diuretic-induced effects has not been proven in clinical practice. 4

Mechanisms of Harm

• Furosemide is associated with worsening renal function, with studies showing patients who developed worsening renal function received a 60 mg greater total daily dose of furosemide (199 mg vs 143 mg) compared to those without deterioration. 1, 3
• The FDA drug label warns that furosemide combined with ACE inhibitors or angiotensin II receptor blockers may lead to severe hypotension and deterioration in renal function, including renal failure. 5
• Excessive diuresis causes dehydration, blood volume reduction, circulatory collapse, and potentially vascular thrombosis—all of which can precipitate or worsen AKI. 5

When Diuretics May Be Appropriate

Volume Overload Management

• Diuretics should only be used in hemodynamically stable patients with AKI who have documented volume overload. 1, 3
• In patients with acute lung injury and AKI without hemodynamic instability, furosemide may facilitate lung-protective ventilation strategies by achieving appropriate fluid balance. 6
• Data from the Fluid and Catheter Treatment Trial showed that higher furosemide doses had a protective effect on mortality specifically in AKI patients with volume overload, while positive fluid balance was associated with higher mortality. 1

Critical Contraindications

• In hemodynamically unstable patients, furosemide can precipitate volume depletion, hypotension, and further renal hypoperfusion—the potential harm outweighs any benefit. 1, 3
• The FDA label warns that in patients at high risk for radiocontrast nephropathy, furosemide can lead to higher incidence of renal function deterioration. 5

Special Population: Cirrhosis with AKI

Immediate Management

• The EASL guidelines recommend discontinuing diuretics immediately if severe hyponatremia (sodium <125 mmol/L), AKI, worsening hepatic encephalopathy, or incapacitating muscle cramps develop. 1
• The International Club of Ascites recommends withdrawing all diuretics as a first-line management step for cirrhotic patients with AKI stage 1. 3
• Furosemide should be stopped if severe hypokalemia (<3 mmol/L) occurs. 1

Restarting Diuretics

• Diuretics should only be restarted after treating underlying causes and only if volume overload persists despite appropriate management. 3
• In cirrhotic patients presenting with GI hemorrhage, renal impairment, hepatic encephalopathy, hyponatremia, or electrolyte abnormalities, these must be corrected before starting diuretic therapy. 1

Monitoring Requirements

Essential Parameters

• The FDA label mandates frequent monitoring of serum electrolytes (particularly potassium), CO2, creatinine, and BUN during the first few months of furosemide therapy and periodically thereafter. 5
• Reversible elevations of BUN are associated with dehydration, which should be avoided particularly in patients with renal insufficiency. 5
• During IV diuretic therapy, monitor hourly urine output, daily renal function, and electrolytes every 12-24 hours. 3

Drug Interactions That Worsen AKI Risk

• Combining furosemide with other nephrotoxic medications increases AKI odds by 53% per nephrotoxin. 3
• The FDA warns that furosemide can increase cephalosporin-induced nephrotoxicity even with minor or transient renal impairment. 5
• Nephrotoxicity of drugs like cisplatin may be enhanced unless furosemide is given in lower doses with positive fluid balance. 5

Common Pitfalls to Avoid

• Never use diuretics to convert oliguric to non-oliguric AKI—this practice lacks evidence of benefit and may cause harm. 3
• Do not assume that achieving diuresis with furosemide indicates improved renal function; a good urinary response may simply be a proxy for residual renal function rather than therapeutic benefit. 6
• Avoid using diuretics in patients with urinary retention (bladder emptying disorders, prostatic hyperplasia, urethral narrowing) as furosemide can cause acute urinary retention. 5
• The KASL guidelines warn that in cirrhotic patients, diuretics should be used in the smallest effective dose once ascites is controlled to prevent complications. 1