TABLE 3.
Population PK parameter estimates, interindividual and interoccasion variability, and precision of estimates
| Parameter (unit)a | % CV (% shrinkage) |
|||
|---|---|---|---|---|
| Population estimate | Interindividual | Interoccasion | % SE | |
| Apparent clearance (liters/h/15 kg0.75) in absence of SIRS | 4.10 | 53 (4.1) | 20 | |
| Apparent vol of distribution (liters/15 kg) | 20.7 | 40 (37) | 62 (dose 1, 41; dose 5, 8.1) | 21 |
| Formation rate constant (h−1) | 1.50 | 17 | ||
| RFMslope [(48 ml/min)−1] | 0.146 | 12 | ||
| Fraction of clearance in the presence of SIRS | 0.478 | 26 | ||
| Terminal half-life of colistin (h) | 4.96b | |||
| SDslope (%) | 20 | |||
| SDintercept (mg/liter) | 0.300 | |||
a
Apparent clearance and volume of distribution for a creatinine clearance of 0 ml/min; RFM, relative fraction of CMS converted to colistin {1 − [RFMslope × creatinine clearance/(48 ml/min)]} (14); RFMslope, slope of RFM change by creatinine clearance; SDslope, proportional residual error; SDintercept, additive residual error (ɛ shrinkage was 12.6%).
b
Median of the individual estimates calculated based on the apparent clearance and apparent volume of distribution (10th to 90th percentile 2.57 to 10.80 h).