A new regimen for continuous infusion of vancomycin during continuous renal replacement therapy.

INTRODUCTION

Continuous infusion (CI) of high-dose vancomycin is often used to treat life-threatening infections caused by less-susceptible Gram-positive bacteria. However, this approach has not been well studied in patients on continuous renal replacement therapy (CRRT). The aim of this study was to evaluate the adequacy of a new CI vancomycin regimen in septic patients undergoing CRRT.

METHODS

In this prospective study we measured vancomycin concentrations obtained with a new CI regimen for CRRT, which included a loading dose of 35 mg/kg given over a 4 h period followed by a daily dose of 14 mg/kg. Vancomycin concentrations were measured: at the end of the loading dose (T1); 12 h after the onset of therapy (T2); and 24 h after the onset of therapy (T3). Drug concentrations (at T2 and T3) were considered adequate if between 20 and 30 mg/L. CRRT intensity was calculated as: dialysate rate (mL/kg/h) + ultrafiltration rate (mL/kg/h). Vancomycin population pharmacokinetics were calculated using non-linear mixed-effects modelling.

RESULTS

We studied 32 patients who received median (IQR) loading and daily vancomycin doses of 2750 mg (2250-3150) and 1100 mg (975-1270), respectively. Drug concentrations were: T1, 44 mg/L (38-58); T2, 27 mg/L (24-31); and T3, 23 mg/L (19-31). Vancomycin concentrations were adequate in 22/32 patients (69%) at T2 and in 20/32 (63%) at T3. The two relevant covariates that significantly affected drug concentrations were body weight and CRRT intensity.

CONCLUSIONS

This new vancomycin regimen allowed the rapid achievement of target drug concentrations in the majority of patients. CRRT intensity had an influence on vancomycin clearance.