Population pharmacokinetics of tazobactam/piperacillin in Japanese patients with community-acquired pneumonia.

The population pharmacokinetics on tazobactam/piperacillin (TAZ/PIPC; 1:8, 4.5 g x 3) was analyzed in Japanese patients with community-acquired pneumonia using the Nonlinear Mixed Effect Model version VI. Analysis by the one-compartment model yielded the following results for PIPC: total clearance (CL) = 8.22+(Ccr-71.4) x 0.0561 (L/hr), distribution volume (Vd) = 13.7 (L). The pharmacokinetic parameters for TAZ were: CL = 8.67 + (Ccr-71.4) x 0.0682 (L/hr), Vd = 14.4 (L). Of the pharmacokinetic parameters of PIPC, CL included Ccr as a variation factor, whereas the Vd included no variation factor. Because PIPC is excreted into the urine in the unchanged form, its pharmacokinetic factors seem to reflect the renal function status. In this study of patients with community-acquired pneumonia, the mean Vd per body weight was 0.26 L/kg, and the results suggested an increase of the Vd in patients with community-acquired pneumonia as compared with the value in healthy adults.