What is the recommended starting dose for a Lasix (furosemide) drip?

Recommended Starting Dose for Furosemide (Lasix) Drip

The recommended starting dose for a Lasix (furosemide) drip is an initial IV bolus of 20-40 mg followed by a continuous infusion at a rate not exceeding 4 mg/minute, with a total dose remaining below 100 mg in the first 6 hours and 240 mg during the first 24 hours. 1, 2

Initial Dosing Algorithm

1. Initial Bolus Administration:

   • Administer 20-40 mg IV furosemide over 1-2 minutes 2, 1
   • Assess response by monitoring urine output 2

2. Continuous Infusion Considerations:

   • For patients with evidence of volume overload who need continuous infusion 2
   • Add furosemide to compatible solutions (Sodium Chloride Injection, Lactated Ringer's, or 5% Dextrose) 1
   • Ensure solution pH is above 5.5 (weakly alkaline to neutral range) 1
   • Administer at a rate not exceeding 4 mg/minute 1

3. Dosing Limits:

   • Total dose should remain < 100 mg in first 6 hours 2
   • Total dose should remain < 240 mg during first 24 hours 2

Special Considerations

• Monitoring Requirements:

  • Place bladder catheter to monitor urinary output and assess treatment response 2
  • Monitor serum electrolytes, especially potassium 2
  • Monitor renal function and blood pressure 2

• Dose Adjustments:

  • Increase dose according to renal function and history of chronic oral diuretic use 2
  • If no response is observed within 1-2 hours, dose may be increased 1
  • For acute pulmonary edema: If satisfactory response not seen within 1 hour after initial 40 mg dose, may increase to 80 mg IV (administered slowly over 1-2 minutes) 1

• Contraindications/Cautions:

  • Use with caution in patients with hypotension (SBP < 90 mmHg) 2
  • Use with caution in patients with severe hyponatremia or acidosis 2
  • Avoid in patients with known hypersensitivity to furosemide 1

Potential Adverse Effects

• Electrolyte Disturbances:

  • Hypokalemia, hyponatremia, hyperuricemia 2
  • Monitor electrolytes closely, especially in first 24 hours 2

• Hemodynamic Effects:

  • Transient worsening of hemodynamics (increased heart rate, mean arterial pressure, LV filling pressure) 2
  • Decreased stroke volume and increased systemic vascular resistance 2

• Renal Effects:

  • Higher loop diuretic doses associated with worsening renal function 2
  • Hypovolemia and dehydration may occur with excessive diuresis 2

Combination Therapy

• Consider adding thiazide diuretics in cases of diuretic resistance 2

  • Hydrochlorothiazide 25 mg PO can be used in combination 2

• Consider adding aldosterone antagonists in volume-overloaded patients 2

  • Spironolactone 25-50 mg PO can be used in combination 2

• Consider vasodilator therapy to reduce the need for high-dose diuretic therapy 2

  • Nitrates may improve cardiac output compared to furosemide alone 2

Important Clinical Pearls

• Furosemide acts at the luminal surface of the ascending limb of the loop of Henle by inhibiting active chloride reabsorption 3
• Response is related to the concentration of the drug in urine rather than in plasma 3
• Parenteral therapy should be replaced with oral therapy as soon as practical 1
• Continuous infusion may provide more stable diuresis than intermittent bolus dosing in patients with severe volume overload 2