What is the maximum recommended dose of Lasix (furosemide) in fusion?

Maximum Dose of Furosemide in Infusion

For continuous IV infusion, the maximum rate is 4 mg/min, with total dose limits of <100 mg in the first 6 hours and <240 mg in the first 24 hours for acute heart failure. 1, 2, 3

FDA-Approved Administration Guidelines

• The FDA label specifies that high-dose parenteral furosemide must be administered as a controlled IV infusion at a rate not greater than 4 mg/min to prevent ototoxicity. 3
• The infusion solution must be prepared by adding furosemide to Sodium Chloride Injection USP, Lactated Ringer's Injection USP, or Dextrose (5%) Injection USP after adjusting pH to above 5.5. 3
• The pH of the prepared infusion must remain in the weakly alkaline to neutral range (pH >5.5), as furosemide may precipitate at pH values below 7. 3

Acute Heart Failure Dosing Limits

• The European Society of Cardiology recommends keeping total furosemide dose below 100 mg in the first 6 hours and below 240 mg during the first 24 hours in acute heart failure. 1, 2
• Initial IV bolus should be 20-40 mg over 1-2 minutes, followed by continuous infusion at 5-10 mg/hour if needed. 1
• For patients already on chronic oral diuretics, the IV dose should be at least equivalent to their oral dose. 1

Higher Dose Infusions in Refractory Cases

• When escalating beyond standard doses, furosemide can be safely increased up to 500 mg per dose in acute pulmonary congestion, but must be given by infusion over 4 hours to prevent ototoxicity. 1
• Research evidence demonstrates that continuous infusion is more efficacious than bolus injection at high doses (mean 690 mg/day, range 250-2,000 mg/day), producing significantly higher urinary volume and sodium excretion with lower risk of hearing loss. 4
• Historical case series report successful use of 0.5-8 g/day in severe refractory cardiac failure, though these extreme doses are rarely employed in modern practice. 5, 6

Critical Safety Considerations

• Doses of 250 mg and above must be given by infusion over at least 4 hours to prevent ototoxicity. 1
• Infusions administered faster than 4 mg/min or given as rapid bolus at high doses carry significant risk of transient or permanent hearing loss. 1, 4
• Five patients in one study experienced short-term, completely reversible hearing loss after bolus injection of high-dose furosemide (mean 690 mg), while none experienced this with continuous infusion. 4

Monitoring Requirements During High-Dose Infusion

• Monitor urine output hourly, with bladder catheter placement recommended for accurate assessment. 1
• Check blood pressure every 15-30 minutes during the first 2 hours. 1
• Assess electrolytes (particularly potassium and sodium) within 6-24 hours. 1, 2
• Monitor renal function within 24 hours of initiation. 1

Contraindications to High-Dose Infusion

• Do not administer furosemide if systolic blood pressure is <90 mmHg without circulatory support, or if marked hypovolemia, severe hyponatremia, or anuria is present. 1, 2
• Acid solutions and acidic medications (labetalol, ciprofloxacin, amrinone, milrinone) must not be administered concurrently in the same infusion line as they cause precipitation. 3

Alternative Strategies When Maximum Infusion Doses Fail

• Consider combination therapy with thiazides (hydrochlorothiazide 25 mg) or aldosterone antagonists (spironolactone 25-50 mg) rather than further escalating furosemide alone. 1, 2
• Sequential nephron blockade is more effective than monotherapy escalation when high doses prove inadequate. 1
• Consider venovenous isolated ultrafiltration if pulmonary edema persists despite maximal medical therapy. 1

Pediatric Infusion Dosing

• The maximum dose for pediatric patients is 6 mg/kg/day, with doses greater than this not recommended. 1, 3, 7
• For premature infants, the maximum dose should not exceed 1 mg/kg/day. 3
• Initial pediatric IV dose is 1 mg/kg given slowly under close medical supervision, with increases of 1 mg/kg not sooner than 2 hours after the previous dose. 3