Vancomycin AUC/MIC and Corresponding Troughs in a Pediatric Population.

Area of Science:

• Pediatric Infectious Diseases
• Pharmacokinetics and Pharmacodynamics
• Antimicrobial Stewardship

Background:

• Adult guidelines recommend vancomycin AUC/MIC > 400 for MRSA, corresponding to trough concentrations of 15-20 mg/L.
• Achieving target vancomycin troughs in pediatric patients is clinically challenging.
• Pediatric vancomycin dosing requires specific pharmacokinetic evaluation.

Purpose of the Study:

• To assess the likelihood of achieving an AUC/MIC > 400 with vancomycin 15 mg/kg every 6 hours in pediatric patients.
• To determine the correlation between vancomycin trough concentrations and AUC/MIC targets in children.
• To evaluate the impact of different pharmacokinetic methods on AUC/MIC calculations.

Main Methods:

• Retrospective chart review of pediatric patients (>2 months to <18 years) with S. aureus bacteremia.
• Patients were grouped based on initial vancomycin dosing (≥15 mg/kg q6h vs. other).
• Area under the curve (AUC) was calculated using three pharmacokinetic methods; trapezoidal equation (Method A) was analyzed for correlation.

Main Results:

• Fifty-five patients received vancomycin ≥15 mg/kg q6h, with 99 trough concentrations assessed.
• The probability of achieving AUC/MIC > 400 varied widely (16.4%–90.9%) with a median trough of 11.4 mg/L in the higher dose group.
• An AUC/MIC of 400 correlated to a trough concentration of 11 mg/L using the trapezoidal method.

Conclusions:

• Vancomycin dosing of 15 mg/kg every 6 hours in children yields variable AUC/MIC > 400 achievement.
• The AUC/MIC target of 400 in pediatric patients correlates to a trough concentration of 11 mg/L when using the trapezoidal method.
• Pharmacokinetic method choice significantly impacts AUC/MIC calculations and target attainment assessment in pediatric vancomycin therapy.