What are the absolute contraindications and major precautions for using furosemide?

Contraindications for Furosemide

Furosemide is absolutely contraindicated in patients with anuria and in those with a history of hypersensitivity to furosemide. 1

Absolute Contraindications

Primary Contraindications from FDA Label

• Anuria – Furosemide cannot work without functioning nephrons and may worsen outcomes 1
• Known hypersensitivity to furosemide – Prior allergic reactions preclude future use 1

Critical Clinical Contraindications from Guidelines

Severe Hyponatremia:

• Serum sodium <120-125 mmol/L is an absolute contraindication requiring immediate discontinuation of furosemide 2
• In cirrhotic patients specifically, sodium <120-125 mmol/L mandates stopping all diuretics 2

Marked Hypovolemia:

• Patients with clinical signs of severe volume depletion (decreased skin turgor, hypotension, tachycardia) should not receive furosemide 2
• Furosemide worsens hypoperfusion and can precipitate cardiogenic shock in hypovolemic states 2

Severe Hypotension:

• Systolic blood pressure <90 mmHg without circulatory support is a contraindication 2
• Furosemide causes further volume depletion and worsens tissue perfusion in hypotensive patients 2

Severe Hypokalemia:

• Potassium <3 mmol/L requires stopping furosemide immediately 2
• Risk of life-threatening arrhythmias increases substantially below this threshold 2

Major Precautions and High-Risk Situations

Conditions Requiring Extreme Caution

Severe Urinary Retention:

• In patients with bladder emptying disorders, prostatic hyperplasia, or urethral narrowing, furosemide can cause acute urinary retention due to increased urine production 1
• These patients require careful monitoring, especially during initial treatment 1

Radiocontrast Nephropathy Risk:

• Patients at high risk for radiocontrast nephropathy who receive furosemide show higher incidence of renal function deterioration compared to those receiving only IV hydration 1
• Avoid furosemide before contrast administration in high-risk patients 1

Hypoproteinemia:

• In nephrotic syndrome or other hypoproteinemic states, furosemide's effect is weakened and ototoxicity is potentiated 1
• Requires dose adjustment and enhanced monitoring 1

Pediatric-Specific Contraindications

Premature Infants:

• Furosemide may precipitate nephrocalcinosis/nephrolithiasis in premature infants 1
• Renal function monitoring and renal ultrasonography are mandatory 1

High-Dose Duration Limits:

• Doses >6 mg/kg/day should never be given for longer than 1 week due to severe ototoxicity risk 3
• This represents a hard stop to prevent permanent hearing loss 3

Critical Drug Interactions

Aminoglycoside Antibiotics:

• Furosemide dramatically increases ototoxic potential of aminoglycosides, especially with impaired renal function 1
• Avoid this combination except in life-threatening situations 1

Ethacrynic Acid:

• Concomitant use is contraindicated due to additive ototoxicity 1
• Never combine these loop diuretics 1

Lithium:

• Lithium generally should not be given with diuretics because they reduce lithium's renal clearance and create high risk of lithium toxicity 1

Cisplatin:

• Risk of ototoxic effects if given concomitantly 1
• Nephrotoxicity may be enhanced unless furosemide is given in lower doses with positive fluid balance 1

Relative Contraindications Requiring Dose Adjustment or Monitoring

Progressive Renal Failure:

• Worsening renal function mandates stopping or reducing furosemide 2
• Furosemide does not treat or prevent acute kidney injury—only manages volume overload complicating AKI 2

Hepatic Encephalopathy:

• Worsening encephalopathy in cirrhotic patients requires immediate discontinuation 2
• Electrolyte disturbances from furosemide can precipitate or worsen encephalopathy 2

Sulfonamide Allergy:

• Patients allergic to sulfonamides may also be allergic to furosemide 1
• However, recent evidence suggests extremely low risk of minor reactions only 4
• Use with caution and monitoring, not an absolute contraindication 4

Systemic Lupus Erythematosus:

• Possibility of exacerbation or activation of SLE exists 1
• Monitor closely for disease flares 1

Common Pitfalls to Avoid

• Never give furosemide expecting it to improve hemodynamics in hypotensive patients—it worsens hypoperfusion 2
• Never use furosemide to prevent or treat AKI itself—only for managing volume overload that complicates AKI 2
• Never exceed 6 mg/kg/day for >1 week in children—permanent hearing loss can result 3
• Never give rapid IV push at high doses—infuse over 5-30 minutes to minimize ototoxicity 2, 3
• Never ignore electrolyte monitoring—check sodium, potassium, and creatinine every 1-2 days initially, then every 3-7 days 2
• Never combine with ethacrynic acid or aminoglycosides without life-threatening indication 1