What is the recommended dose of vancomycin for pediatric patients with varying degrees of renal function and infection severity?

Vancomycin Dosing in Pediatric Patients

Standard Dosing Recommendations

For children aged 1 month to 18 years with normal renal function and serious infections, vancomycin should be dosed at 15 mg/kg every 6 hours (60 mg/kg/day total), with target trough concentrations of 15-20 mg/L. 1

Age-Specific Dosing Guidelines

Neonates (≤1 month):

• Initial dose: 15 mg/kg, followed by 10 mg/kg every 12 hours for the first week of life, then every 8 hours thereafter up to 1 month of age 2
• Each dose should be administered over at least 60 minutes 2
• Premature infants require longer dosing intervals due to decreased vancomycin clearance as postconceptional age decreases 2

Infants and Children (1 month to 12 years):

• Standard dose: 15 mg/kg every 6 hours (60 mg/kg/day) for serious infections 3, 1
• For patients with augmented renal clearance (ARC): increase to 75 mg/kg/day divided every 6 hours 4
• Maximum single dose should not exceed 2 grams 1

Adolescents (12-18 years):

• Standard dose: 15 mg/kg every 6 hours (60 mg/kg/day) 1
• For patients with ARC: 70 mg/kg/day divided every 6 hours 4

Dosing Based on Infection Severity

For complicated intra-abdominal infections:

• 40 mg/kg/day divided every 6-8 hours as a 1-hour infusion 3
• Antibiotic serum concentrations and renal function should be monitored 3

For severe or invasive disease:

• 60 mg/kg/day divided every 6 hours with target trough concentrations of 15-20 mg/L 1
• Higher doses (up to 85 mg/kg/day) may be required to achieve trough concentrations of 15 mg/L in some patients 5

Dosing Adjustments for Renal Impairment

Children with renal insufficiency require dose reduction based on creatinine clearance while maintaining weight-based dosing per dose. 6

Practical Dosing Algorithm for Renal Dysfunction

• Mild renal impairment (SCr 0.9-1.5 mg/dL): 45 mg/kg/day divided every 8 hours achieves target AUC/MIC ≥400 in 80% of patients 6
• Moderate to severe impairment: Extend dosing intervals to every 12-24 hours based on creatinine clearance, maintaining 15 mg/kg per dose 6
• Loading dose: Always give full 15 mg/kg loading dose regardless of renal function 1

Critical consideration: Renal function may recover during therapy in 87% of children with acute renal impairment, requiring dose adjustments upward as kidney function improves 6

Dosing for Obese Pediatric Patients

Use total body weight for all vancomycin dose calculations in obese children. 7

• Obese children (BMI >95th percentile) require the same mg/kg dosing as normal-weight children when using total body weight 7
• A practical dosing guideline integrating both body weight and creatinine clearance performs well across all weight ranges (6-188 kg studied) 7
• Standard 60 mg/kg/day dosing based on total body weight achieves therapeutic exposures in obese pediatric patients 7

Therapeutic Monitoring

Obtain trough concentrations before the fourth dose (at steady state) to guide dosing adjustments. 1

Target Trough Concentrations

• Serious infections (bacteremia, endocarditis, osteomyelitis, meningitis, pneumonia): 15-20 mg/L 1
• Less severe infections: 10-15 mg/L 1
• Complicated intra-abdominal infections: Monitor concentrations and adjust to maintain therapeutic levels 3

Monitoring Frequency

• Mandatory monitoring for all patients receiving aggressive dosing targeting 15-20 mg/L 1
• Close monitoring warranted in neonates, premature infants, and patients with changing renal function 2
• Frequent monitoring required for prolonged therapy or unstable renal function 1

Administration Guidelines

Infuse each dose over a minimum of 60 minutes, regardless of dose size. 2

• For doses >1 gram, extend infusion to 1.5-2 hours to minimize red man syndrome risk 1
• Maximum concentration: 5 mg/mL (up to 10 mg/mL in fluid-restricted patients, though this increases infusion reaction risk) 2
• Maximum infusion rate: 10 mg/min 2

Common Pitfalls and Caveats

Underdosing is the most common error in pediatric vancomycin therapy. The traditional 40 mg/kg/day dosing results in subtherapeutic concentrations in most children when targeting trough levels of 10-20 mg/L 5

Critical Errors to Avoid

• Never use fixed doses (e.g., 500 mg every 6 hours) - always calculate based on mg/kg 8
• Do not reduce loading doses in renal impairment - the loading dose fills the volume of distribution, which is unchanged by kidney function 1
• Avoid conventional 40-60 mg/kg/day dosing for serious infections - this achieves therapeutic troughs in only 49% of patients 5
• Do not assume peak concentrations - trough >5 mg/L predicts peak >20 mg/L with 81% accuracy, but routine peak monitoring may still be needed for serious infections 8

Special Population Considerations

PICU patients require higher doses than general pediatric patients. Initial dosing of 60 mg/kg/day divided every 8 hours is recommended for critically ill children with normal renal function 8

Patients with augmented renal clearance are at high risk of underdosing. Standard 60 mg/kg/day dosing results in mean trough concentrations of only 6.5 mg/L in children with ARC 4

Pharmacodynamic Targets

The AUC/MIC ratio >400 is the pharmacodynamic parameter that best predicts vancomycin efficacy. 1

• For organisms with MIC ≤1 mg/L, trough-based dosing targeting 15-20 mg/L typically achieves AUC/MIC >400 1
• For organisms with MIC ≥2 mg/L, consider alternative antibiotics as target ratios may not be achievable 1
• Body weight and age are the most significant covariates affecting vancomycin clearance and volume of distribution in children 7, 4