TABLE 5.
Population pharmacokinetic model parameter estimates and standard errors for lopinavir and ritonavir in the presence of nevirapine or efavirenza
| Drug and parameter | Value |
|||||||
|---|---|---|---|---|---|---|---|---|
| Efavirenz |
Nevirapine |
|||||||
| Estimate | RSE (%) | IOV (%) | RSE (%) | Estimate | RSE (%) | IOV (%) | RSE (%) | |
| Lopinavir | ||||||||
| CL/F (liters/h) | 6.81 | 6.0 | 17.4 | 47.4 | 6.54 | 4.1 | 11.0 | 43.9 |
| V/F (liters) | 104 | 13.0 | 138 | 11.5 | ||||
| ka (h−1) | 1.22 | 1.22 | ||||||
| Factor associated with RTV AUC0-12 on CL/F | −0.633 | 13.2 | −0.612 | 11.0 | ||||
| Relative change in LPV CL/F for 600/150 mg | 0.415 | 5.1 | 0.434 | 7.2 | ||||
| Relative change in LPV CL/F for 400/100 mg | 0.986 | 6.8 | 0.929 | 5.3 | ||||
| Residual error, proportional (%) | 39.5 | 14.3 | 33.3 | 15.9 | ||||
| Ritonavir | ||||||||
| CL/F (liters/h) | 37.7 | 7.2 | 14.2 | 51.0 | 36.6 | 5.5 | 15.1 | 43.5 |
| V/F (liters) | 42.1 | 30.9 | 42.1 | |||||
| ka (h−1) | 0.111 | 13.7 | 0.0819 | 17.0 | ||||
| Factor associated with LPV AUC0-12 on CL/F | −0.882 | 9.9 | −1.12 | 7.4 | ||||
| Relative change in RTV CL/F for 600/150 mg | 0.421 | 7.6 | 0.452 | 5.9 | ||||
| Relative change in RTV CL/F for 400/100 mg | 0.856 | 7.6 | 0.872 | 8.0 | ||||
| Residual error | ||||||||
| Proportional (%) | 29.5 | 40.0 | 41.5 | 20.2 | ||||
| Additive (mg/liter) | 0.058 | 46.6 | 0.039 | 40.1 | ||||
a
CL/F, apparent oral clearance of lopinavir; V/F, apparent volume of distribution; ka, absorption rate constant; LPV, lopinavir; RTV, ritonavir; AUC0-12, area under the concentration-time curve over the dosing interval; RSE, relative standard error; IOV, interoccasion variability [RSE = (SEestimate/estimate) × 100].