INFLUENCE OF PHARMACOKINETIC MODEL ON VANCOMYCIN PEAK CONCENTRATION TARGETS

The aim of this study was to adapt the vancomycin therapeutic range to the kinetic models usually employed in clinical settings (one- and tw o-compartment models). Estimates of vancomycin pharmacokinetic paramet ers were obtained for both models in 22 hematologically malignant pati ents on vancomycin treatment using two serum concentrations and a baye sian algorithm. From these individually estimated pharmacokinetic para meters, an estimation of the maximum (C-max(ss)), 2 h postinfusion (C- 2(ss)), and minimum (C-min(ss)) steady-state vancomycin serum concentr ations for the one- and two-compartment models was made for a fixed 30 mg/kg/day dose. The linear regression equations between the predicted C-2(ss) and C-min(ss) for the one- and two-compartment models do not differ significantly from the identity line, whereas the corresponding equation for C-max(ss) points to a 61% underestimation of C-max(ss) w hen the one-compartment model is used. From this latter regression equ ation, it is possible to define 20 mg/L (range of 18-21 mg/L) as a tar get C-max(ss) vancomycin serum concentration when a one-compartment mo del is used to monitor vancomycin therapy. Another practical approach would be to define the target concentration by a desired range at 2 h, which corresponds to a C-max(ss) value of 30-40 mg/L.