Optimizing initial vancomycin dosing in burn patients.

RATIONALE

Burned patients have altered vancomycin pharmacokinetics necessitating adjusted dosing. Published initial dosing recommendations to target troughs of 15-20mg/L for this population are lacking.

OBJECTIVE

This study was conducted to develop initial vancomycin dosing recommendations based on the pharmacokinetics of vancomycin in acute burn patients.

METHODS

A retrospective chart review of 49 vancomycin treated burn patients was conducted. Mean pharmacokinetic parameters were determined and Monte Carlo Simulation was used to develop initial vancomycin dosing recommendations that target trough concentrations between 15 and 20mg/L.

RESULTS

Vancomycin pharmacokinetic parameters were significantly (p < 0.05) different for vancomycin levels obtained 48 h to 14 days after burn versus >14 days after burn. Monte Carlo simulation indicated that the most commonly used empiric dosing regimen (1g iv q12 h) attained targets with a probability of <10% in all burned patients. The probability of attaining targets was optimized to 20-25% by using 1.5 g iv q8 h, 1.75 g iv q8 h, 1g iv q6 h, 1.25g iv q6 h or 750 mg iv q4 h in patients 48 h to 14 days after burn and 1-1.25 g iv q8 h or 500 mg iv q4 h in patients >14 days after burn.

CONCLUSIONS

This study provides initial vancomycin dosing recommendations for burned patients 48 h to 14 days after burn and patients >14 days after burn. However, because of the heterogeneity in pharmacokinetics and the observation that vancomycin pharmacokinetics change with time after burn, monitoring of vancomycin serum concentrations is required to ensure targets are met and maintained.