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 fro m 49 patients obtained in routine drug monitoring. The one-compartment linear model was adopted, where the VCM clearance (CL) and the distri bution volume (V-d) were correlated with covariates such as postnatal age (AGE) and body weight (BWT). The population pharmacokinetic analys is program NONMEM with the first-order conditional estimation method w as used. The results showed that the population mean clearance normali zed by BWT increases with AGE up to 1 year of age [CL(L/hour per kg) = 0.119 +/- 0.0619 . (AGE - 1)] and decreases with age over 1 year old [CL(L/hour per kg) = 0.119 +/- 0.00508 . (1 - AGE)]. The population me an of the distribution volume normalized by BWT was independent of AGE (V-d (L/kg) = 0.522). The interindividual variability of CL was 39.6% , and that of V-d 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.