Table 2.
Piperacillin population pharmacokinetic parameter estimates obtained by Pmetricsa
| Model and drug | Parameter and result (mean ± SD [median]) |
|||||
|---|---|---|---|---|---|---|
| Vmax (mg/h) | Km (mg/liter) | Vc (liter) | Kcp (h−1) | Kpc (h−1) | SCL (liter/h) | |
| Piperacillin | ||||||
| Linear | 18.90 ± 9.19 (16.41) | 2.62 ± 3.91 (0.57) | 28.38 ± 17.41 (39.62) | 17.44 ± 6.09 (15.14) | ||
| Michaelis-Menten | 1,634.68 ± 597.33 (1863.70) | 78.57 ± 52.51 (89.69) | 13.10 ± 7.13 (14.73) | 12.80 ± 9.97 (11.83) | 20.89 ± 14.72 (30.09) | |
| Parallel First-Order/MM | 898.91 ± 402.61 (808.31) | 90.13 ± 74.14 (77.43) | 13.67 ± 7.20 (15.78) | 9.19 ± 10.25 (3.79) | 20.95 ± 16.91 (28.58) | 6.62 ± 3.81 (6.89) |
| Tazobactam | ||||||
| Linear | 21.13 ± 10.75 (20.31) | 5.96 ± 11.77 (0.37) | 29.10 ± 17.14 (39.69) | 15.16 ± 4.63 (13.68) | ||
a
Vmax is the maximum elimination rate; Km is the Michaelis-Menten constant; Vc is the apparent volume of distribution of the central compartment; Kcp and Kpc are first-order intercompartmental transfer rate constants; SCL is clearance; MM is Michaelis-Menten.