What is the recommended dosage of vancomycin for a newborn?

Vancomycin Dosing for Newborns

For newborns, vancomycin dosing must be stratified by both postnatal age and birth weight, with doses ranging from 10-20 mg/kg given at intervals of 8-24 hours depending on these parameters. 1

Dosing Algorithm by Age and Weight

Neonates ≤7 Days Postnatal Age

• <1200g: 15 mg/kg/day given every 24 hours 1, 2
• 1200-2000g: 10-15 mg/kg given every 12-18 hours 1, 2
• >2000g: 10-15 mg/kg given every 8-12 hours 1, 2

Neonates >7 Days Postnatal Age

• <1200g: 15 mg/kg/day given every 24 hours 1, 2
• 1200-2000g: 10-15 mg/kg given every 8-12 hours 1, 2
• >2000g: 15-20 mg/kg given every 8 hours 1, 2

Initial Dosing Approach

Start with a loading dose of 15 mg/kg for all neonates, followed by maintenance dosing based on the weight and age categories above. 3 This loading dose is critical to rapidly achieve therapeutic concentrations, particularly in seriously ill neonates. 3

Administration Guidelines

• Each dose must be infused over at least 60 minutes to minimize the risk of infusion-related reactions, particularly "red man syndrome." 3, 2
• For larger doses or loading doses, consider extending the infusion time beyond 60 minutes to further reduce adverse reaction risk. 2
• Concentrations should not exceed 5 mg/mL in most cases, though up to 10 mg/mL may be used in fluid-restricted patients with increased infusion-related event risk. 3

Therapeutic Monitoring

Therapeutic drug monitoring is essential in neonates due to significant pharmacokinetic variability. 2, 4

• Target trough concentrations of 10-20 mg/L are generally recommended. 2
• Obtain serum vancomycin concentrations at steady state, typically before the fourth or fifth dose. 2
• Premature infants require particularly close monitoring as vancomycin clearance decreases with decreasing postconceptional age. 3, 5

Special Considerations and Pitfalls

The most common error is using fixed dosing without accounting for postnatal age and weight, which leads to either subtherapeutic levels or toxicity. 4, 6

• Premature neonates (<1000g) have significantly prolonged half-lives and require longer dosing intervals. 3, 5
• Neonates receiving indomethacin concurrently may require 50% dose reduction due to decreased vancomycin clearance. 6
• Renal function changes rapidly in the first weeks of life; dosing intervals must be adjusted accordingly even with normal serum creatinine. 3, 6
• Volume of distribution remains relatively constant at approximately 0.5-0.6 L/kg across gestational ages, but clearance increases significantly with postconceptional age. 6, 5

Alternative Dosing Strategy

For neonates requiring more consistent drug levels, continuous infusion may be considered at 25-30 mg/kg/day following a 10 mg/kg loading dose, targeting steady-state concentrations of 20-25 mg/L. 7 However, this approach requires careful monitoring and is less commonly used than intermittent dosing. 7