What is the recommended dosage of Lasix (furosemide)?

Recommended Dosage of Furosemide (Lasix)

The recommended initial dosage of furosemide is 20-80 mg given as a single oral dose for adults with edema, with dose adjustments based on clinical response. 1

Adult Dosing Guidelines by Condition

Heart Failure

• Initial dose: 20-40 mg orally or intravenously 2
• For acute heart failure: 20-40 mg IV bolus at admission 2
• Maximum dose limits: <100 mg in first 6 hours and <240 mg during first 24 hours 2
• For severe refractory cardiac failure: doses may be increased up to 600 mg/day with careful monitoring 1
• Maintenance therapy: Lowest effective dose to maintain minimal or no symptoms 1

Liver Failure with Ascites

• Initial regimen: 40 mg furosemide combined with 100 mg spironolactone (100:40 ratio) 3, 2
• Doses may be increased simultaneously every 3-5 days while maintaining the 100:40 ratio 2
• Maximum furosemide dose: 160 mg/day (threshold for determining medical treatment refractoriness) 3
• For tense ascites: Large-volume paracentesis with albumin is the initial treatment of choice 3

Edema (General)

• Starting dose: 20-80 mg as a single dose 1
• Dose may be repeated after 6-8 hours or increased if needed 1
• Dose increases should be in increments of 20 or 40 mg 1
• For efficient edema mobilization: Give on 2-4 consecutive days each week 1

Special Populations

Pediatric Patients

• Initial dose: 2 mg/kg body weight as a single dose 1
• If response is inadequate, may increase by 1-2 mg/kg no sooner than 6-8 hours after previous dose 1
• Maximum recommended dose: 6 mg/kg body weight 1
• For infants with normal renal function: 1 mg/kg IV may be sufficient as higher doses may not significantly increase diuretic response 4

Geriatric Patients

• Start at the lower end of the dosing range 1
• Careful dose adjustment based on response and tolerability 1

Patients with Renal Impairment

• Higher doses of loop diuretics may be required 3
• In acute renal failure: Total daily dose should not exceed 100 mg 4

Administration Considerations

• Single morning dosing maximizes compliance 2
• For twice-daily dosing, administer at 8 am and 2 pm 1
• When doses exceed 80 mg/day for prolonged periods, careful clinical and laboratory monitoring is essential 1

Monitoring and Precautions

• Monitor urine output, especially in acute heart failure (consider bladder catheterization) 2
• Watch for electrolyte abnormalities, particularly hypokalemia and hyponatremia 2, 1
• Use cautiously in patients with hypotension as it may worsen hemodynamic status 2
• For diuretic resistance, consider combination therapy with thiazides or aldosterone antagonists 2
• When used with other antihypertensives, reduce other agents' doses by at least 50% initially 1

Common Pitfalls and Caveats

• Avoid excessive diuresis leading to hypovolemia, which can worsen renal function 2
• For patients with cirrhosis and ascites, diuretics should be stopped in cases of hepatic encephalopathy, severe hyponatremia, or acute kidney injury 3
• High-dose furosemide therapy may lead to ototoxicity, particularly with rapid IV administration 3
• Furosemide infusions exceeding 6 mg/kg/day should not be given for periods longer than 1 week 3
• In congestive heart failure, some patients can be maintained on lower doses (20 mg daily), highlighting the importance of periodic reevaluation of diuretic requirements 5