Correlation of a Vancomycin Pharmacokinetic Model and Trough Serum Concentrations in Pediatric Patients

Abstract

Vancomycin trough concentrations specific to pediatric patients have yet to be validated that achieve an area under the curve (AUC) over 24 hours to minimum inhibitory concentration (MIC) ratio ≥400. The primary objective of this study was to validate a pharmacokinetic model in a pediatric hospital and determine the correlation between a calculated AUC/MIC ratio and measured trough vancomycin concentration. A retrospective evaluation of patients aged 3 months to 18 years prescribed vancomycin at a pediatric hospital between January 2012 and June 2013. The correlation between patient-specific AUC/MIC and measured vancomycin trough concentration was assessed. Forty pediatric patients with 40 vancomycin trough concentrations and documented Staphylococcus aureus cultures were included in the study. Median age was 8.5 (interquartile range, 2-14.3) years, median weight 28.7 (range, 14-50.2) kg, and mean baseline serum creatinine 0.51 ± 0.3 mg/dL. The mean daily dose of vancomycin prescribed was 58 ± 13.8 mg/kg/d. The mean vancomycin trough concentration was 11 ± 5.5 mcg/mL, and the mean AUC/MIC was 534 ± 373. No correlation was found between trough concentration and AUC/MIC (r = 0.082, p = 0.07). This study validates the clinical applicability of a pharmacokinetic model for calculating vancomycin clearance to determine patient-specific AUC over 24 hours in pediatrics. Trough concentrations associated with proposed therapeutic AUC/MIC ratios were lower than reported in the adult population. Further research is needed to determine if AUC/MIC, trough concentration, or both is best for monitoring therapeutic efficacy of vancomycin in pediatrics.