Vancomycin is commonly under-dosed in critically ill children and neonates

Abstract

Aims: Vancomycin is frequently used in critically ill children in whom the drug pharmacokinetics are significantly altered as a result of changes in renal clearance and volume of distribution. Therapeutic drug monitoring (TDM) is recommended to achieve vancomycin trough concentrations between 10 and 20 mg/L. In this study we reviewed vancomycin dosing, TDM and treatment outcomes in paediatric and neonatal intensive care unit patients.

Methods: We reviewed the medical records of all patients receiving intravenous vancomycin in a tertiary paediatric and neonatal intensive care unit over a 10-month period. Demographic, vancomycin dosing, TDM and drug-related adverse effects data were collected.

Results: In total, 115 children received 126 courses of vancomycin and had at least 1 TDM blood sample taken at steady state. In only 38/126 (30%) courses was the target concentration (10-20 mg/L) achieved at the initial steady state trough sample. Of the 88 courses that had initial trough concentrations outside the target range, the dose was adjusted in only 49 (56%). Overall, minimum doses of 30 mg/kg/day in neonates with a corrected gestational age of <35 weeks, and 50 mg/kg/day in older children, were required to achieve target vancomycin concentrations. Vancomycin-attributable nephrotoxicity occurred in 10/126 (8%) courses and there were no episodes of red man syndrome.

Conclusion: In critically ill children, individualised dosing is needed. In the absence of Bayesian model-based dosing, in children with normal renal function, empiric vancomycin doses of at least 30 mg/kg/day in neonates of <35 weeks corrected gestational age, and 50 mg/kg/day in older children, should be considered. Optimisation of TDM practices through the development of protocols, ideally built into electronic medical records, should be considered.

Keywords: children; dosing; glycopeptide; neonates; pharmacokinetics; therapeutic drug monitoring.

Figure 1

Box plot denotes median, with box depicting 25^th and 75^th percentiles, whiskers depicting maximum and minimum values. CGA, corrected gestational age; w, weeks; m, months