TABLE 2.
Final population pharmacokinetic model parameters of piperacillin and tazobactama
| Parameter | Final piperacillin model |
Final tazobactam model |
||
|---|---|---|---|---|
| Estimate (% SE) | % shrinkage | Estimate (% SE) | % shrinkage | |
| θ1 (liters/h) | 3.51 (6.5) | NA | 3.43 (5.9) | NA |
| θ2 (liters) | 6.58 (10.6) | NA | 5.54 (8.9) | NA |
| θ3 | 0.0814 (45.1) | NA | −0.285 (20.9) | NA |
| θ4 (liters/h) | NA | NA | 0.0676 (38.6) | NA |
| Interindividual variability (ω) | ||||
| ωCL | 17.3% (59.0) | 10.3% | 13.1% (52.1) | 11.2% |
| ωV | 25.2% (59.1) | 18.0% | NA | NA |
| Residual error (σ) | ||||
| σproportional | 25.3% (28.7) | 10.3% | 27.2% (35.2) | 5.8% |
| σadditive | NA | NA | 0.76 mg/liter (47.8) | 5.8% |
a
The final piperacillin model was TVCL = θ1 + [θ3 · (WT − 18)] and TVV = θ2. The final tazobactam model was TVCL = [θ1 · (1 + θ3 · sex)] + [θ4 · (WT − 18)] and TVV = θ2, where sex is coded 1 if female and 0 otherwise, TVCL is the typical population value of clearance (in liters per hour), WT is body weight (in kilograms), and TVV is the typical population value of the volume of distribution (in liters). NA, not applicable.