What is the maximum dose of oral Furosemide (Lasix) per day?

Maximum Oral Furosemide (Lasix) Dosage

The maximum oral dose of furosemide (Lasix) is 600 mg per day in patients with clinically severe edematous states, as indicated in the FDA drug label. 1

Dosing Guidelines for Oral Furosemide

Adult Dosing

• Initial dose: 20-80 mg as a single dose
• Dose titration: May increase by 20-40 mg increments
• Dosing interval: No sooner than 6-8 hours after previous dose
• Maintenance dosing: Once or twice daily (e.g., 8 am and 2 pm)
• Maximum daily dose: 600 mg/day for severe edematous states 1
• Intermittent dosing strategy: For efficient and safe edema mobilization, consider giving furosemide on 2-4 consecutive days each week 1

Special Considerations

High-Dose Therapy

When doses exceeding 80 mg/day are used for prolonged periods:

• Careful clinical observation is required
• Regular laboratory monitoring is essential 1
• Monitor for electrolyte depletion, particularly potassium, sodium, and magnesium 2
• Assess renal function regularly, especially when used with ACE inhibitors or ARBs 2

Potential Adverse Effects with High Doses

• Ototoxicity (especially with cumulative doses above 100-120 g) 3
• Electrolyte imbalances (hypokalemia, hyponatremia, hypomagnesemia) 3, 2
• Dehydration and hypovolemia
• Impaired renal function
• Decreased blood pressure and exercise tolerance 3

Monitoring Recommendations

When using high-dose furosemide therapy:

1. Regular assessment of symptoms and signs of congestion
2. Daily weight measurements
3. Monitoring of urine output
4. Regular assessment of renal function
5. Frequent electrolyte monitoring 2

Practical Considerations

• The European Society of Cardiology recommends using the lowest effective dose to maintain euvolemia while minimizing renal dysfunction 2
• For heart failure patients, doses should be carefully titrated based on response
• When doses exceed 80 mg/day, careful monitoring becomes particularly important 1
• Consider combination therapy with thiazide diuretics for resistant edema, though this increases the risk of adverse effects 3, 2

Pitfalls to Avoid

• Excessive diuresis leading to volume depletion and worsening renal function
• Inadequate monitoring of electrolytes, particularly when using high doses
• Failure to adjust dosing based on renal function
• Ignoring electrolyte depletion, which can lead to serious cardiac arrhythmias, particularly in patients on digitalis therapy 3

The maximum dose of 600 mg/day should be reserved for patients with severe edematous states who require aggressive diuresis and should be accompanied by appropriate monitoring for adverse effects and electrolyte imbalances.