Population Pharmacokinetics of Vancomycin in Japanese Pediatric Patients

The population pharmacokinetic profile of vancomycin (VCM) in Japanese pediatric patients infected with methicillin-resistant Staphylococcus aureus was analyzed using 181 samples of serum concentration data from 49 patients obtained in routine drug monitoring. The one-compartment linear model was adopted, where the VCM clearance (CL) and the distribution volume (Vd) were correlated with covariates such as postnatal age (AGE) and body weight (BWT). The population pharmacokinetic analysis program NONMEM with the first-order conditional estimation method was used. The results showed that the population mean clearance normalized by BWT increases with AGE up to 1 year of age [CL(L/hour per kg) = 0.1 19 + 0.0619 x (AGE - 1)] and decreases with age over 1 year old [CL(L/hour per kg) = 0.119 + 0.00508 x (1 - AGE)]. The population mean of the distribution volume normalized by BWT was independent of AGE (Vd (L/kg) = 0.522). The interindividual variability of CL was 39.6%, and that of Vd was 18.8%. The intraindividual, residual variability was 34.6%. These results were compared with those in other articles, and a guideline for dosage adjustment in VCM therapy is discussed.