Development of a new pharmacokinetic model for target-concentration controlled infusion of vancomycin in critically ill patients.

The aim of this prospective study was to construct a new pharmacokinetic model of vancomycin for target-concentration controlled infusion (TCI). As the first loading dose, 25 mg/kg of vancomycin was administered during 60-90 min. Arterial blood samples were obtained at pre-set intervals to measure the serum concentrations of vancomycin. Population pharmacokinetic analysis was performed using the NONMEM software (ICON Development Solutions). In total, 197 serum concentration measurements from 22 patients were used to characterise the pharmacokinetics of vancomycin. A three-compartment mammillary model best described the pharmacokinetics of vancomycin in critically ill patients. The ideal body weight was a significant covariate for the central and slow peripheral volume of distribution. The weight and age converted to categorical variables at a cut-off of 65 years were a significant covariate for the clearance. Based on the results of stochastic simulation, the TCI method maintained the therapeutic concentration range for the longest duration. In addition, assuming that vancomycin was administered by the TCI method for 7 days, the dose was reduced by about 15% compared with the standard administration methods. The daily area under the curve values were maintained between 500 mg·h/L and 600 mg·h/L. TCI has the potential to become a new infusion method for patient-tailored dosing in critically ill patients. To administer vancomycin via TCI in clinical practice, the newly constructed pharmacokinetic model should undergo proper external validation.