What is the recommended dose of Lasix (furosemide) for a 1-year-old pediatric patient weighing 6.68 kg?

Furosemide Dosing for a 1-Year-Old Weighing 6.68 kg

For this 1-year-old patient weighing 6.68 kg, administer furosemide 6.68 mg IV as the initial dose, given slowly over 1-2 minutes.

Initial Dosing Calculation

• The FDA-approved initial dose for pediatric patients is 1 mg/kg body weight, administered intravenously or intramuscularly under close medical supervision 1
• For a patient weighing 6.68 kg, this calculates to 6.68 mg as the starting dose 1
• The injection must be given slowly (over 1-2 minutes) to minimize adverse effects 1

Dose Titration if Needed

• If the diuretic response to the initial 1 mg/kg dose is not satisfactory, the dosage may be increased by 1 mg/kg (to 2 mg/kg total, or 13.36 mg for this patient) 1
• This increased dose should not be given sooner than 2 hours after the previous dose 1
• Continue titrating by 1 mg/kg increments every 2 hours until the desired diuretic effect is achieved 1
• Doses greater than 6 mg/kg body weight (40 mg for this patient) are not recommended 1

Critical Age-Specific Consideration

• At 1 year of age, this patient falls into the pediatric weight-based dosing category, requiring calculation based on actual body weight rather than fixed adult dosing 2
• The 40 kg threshold that determines adult versus pediatric dosing does not apply here—this patient requires strict mg/kg calculations 2

Important Safety Precautions

• Close medical supervision is mandatory during furosemide administration in pediatric patients 1
• Monitor for fluid and electrolyte disturbances, particularly hypokalemia (3.6% incidence) and intravascular volume depletion (4.6% incidence) 3
• The most common adverse reactions are extensions of therapeutic effects, including fluid and electrolyte disturbances 4
• Careful clinical observation and laboratory monitoring are particularly advisable when furosemide is given for prolonged periods 1

Pharmacodynamic Considerations

• The diuretic response correlates with urinary excretion rate rather than plasma concentration—the drug must reach the tubular lumen to be effective 4, 5
• In infants with reasonably normal renal function, a very steep dose-response curve exists at 1 mg/kg IV, suggesting higher doses may not significantly increase diuretic response 5
• The lowest mean furosemide urinary excretion rate associated with significant diuresis in infants is 0.58 ± 0.33 μg/kg/min 5

Route and Administration Details

• Parenteral therapy should only be used in patients unable to take oral medication or in emergency situations, and should be replaced with oral therapy as soon as practical 1
• The IV route is preferred for acute situations requiring rapid diuresis 1
• If using continuous infusion for high-dose therapy, the rate should not exceed 4 mg/min, and the solution pH must be maintained above 5.5 to prevent precipitation 1

Common Pitfall to Avoid

• Do not use adult fixed dosing (20-40 mg) for this pediatric patient—weight-based calculation is mandatory at this age and weight 1
• Avoid concurrent administration with acidic solutions or medications (labetalol, ciprofloxacin, amrinone, milrinone) as they may cause precipitation 1