Lasix Dosing for a 1-Year-Old Weighing 5.5 kg
The recommended initial dose of oral Lasix (furosemide) for this 1-year-old child weighing 5.5 kg is 11 mg given as a single dose (calculated as 2 mg/kg body weight). 1
Dosing Algorithm
Initial dose: 2 mg/kg body weight as a single dose 1
- For a 5.5 kg child: 2 mg/kg × 5.5 kg = 11 mg
Dose adjustment if needed: If the diuretic response is not satisfactory after the initial dose, the dosage may be increased by 1 or 2 mg/kg no sooner than 6 to 8 hours after the previous dose 1
- Second dose range if needed: 16.5 mg to 22 mg (3-4 mg/kg)
Maximum dose: Doses greater than 6 mg/kg body weight are not recommended 1
- For this child: maximum 33 mg per dose
Maintenance therapy: Once diuresis is achieved, adjust the dose to the minimum effective level 1
Practical Considerations
Formulation: Furosemide is available as tablets (20,40,80 mg) and oral suspension (10 mg/mL concentration when reconstituted) 1
- For an 11 mg dose, use 1.1 mL of the oral suspension (if using 10 mg/mL concentration)
Timing: The same dose can be administered 6 to 8 hours later if needed, or the dose may be increased 1
Monitoring: Careful clinical observation is essential, as the diuretic response correlates with urinary furosemide excretion rates rather than plasma concentrations 2, 3
Important Caveats
Renal function dependency: The severity of any underlying renal impairment significantly affects diuretic response; children with compromised renal function may require higher doses but also face greater risk of adverse effects 3
Electrolyte monitoring: The most common adverse reactions are fluid and electrolyte disturbances (hypokalemia, hyponatremia, metabolic alkalosis) 1
Long-term use risks: Prolonged furosemide treatment in infants has been associated with cholelithiasis (especially with concurrent total parenteral nutrition), secondary hyperparathyroidism, and bone disease 2
Bioavailability variability: Oral furosemide has highly variable bioavailability, which may contribute to unpredictable responses 4