Table 3.
Pharmacokinetic estimates for the final models of rifampin, isoniazid, pyrazinamide, and ethambutol. Ka, absorption rate constant; V, volume of distribution in the central compartment; V2, volume of distribution of the peripheral compartment; Cl, systemic clearance; Cl2, intercompartmental clearance; Tlag, lag-time. %CV, coefficient of variation or precision; IIV, inter-individual variation.
| Drug | Parameter | Final Model | |
|---|---|---|---|
| Estimate (%CV) | IIV (Shrinkage) | ||
| Rifampin | Ka (1/h) | 0.3 (13.5) | 0.01 (0.9) |
| V (L) | 25.3 (33.3) | 3.2 (0.2) | |
| Cl (L/h) | 0.1 (49.6) | 0.2 (0.3) | |
| Tlag (h) | 0.9 (9.1) | 0.003 (0.8) | |
| Isoniazid | Ka (1/h) | 0.9 (0.9) | 0.9 (0.3) |
| V (L) | 2.9 (3) | 0.07 (0.6) | |
| V2 (L) | 32.5 (5.7) | 0.5 (0.7) | |
| Cl (L/h) | 9.2 (8.7) | 0.8 (0.1) | |
| Cl2 (L/h) | 9.6 (3) | 0.0001 (0.9) | |
| Tlag (h) | 0.4 (8.6) | 0.5 (0.5) | |
| Pyrazinamide | Ka (1/h) | 0.08 (13) | 0.1-0.11 |
| V (L) | 1.5 (16.3) | 0.9 (0.4) | |
| Cl (L/h) | 2.6 (14.5) | 0.4 (0.05) | |
| Tlag (h) | 0.2 (7.1) | 1.3 (0.4) | |
| Ethambutol | Ka (1/h) | 0.15 (21.8) | 0.6 (0.4) |
| V (L) | 75.17 (23.7) | 0.4 (0.1) | |
| Cl (L/h) | 51.6 (12.2) | 0.3 (0.3) | |
| Tlag (h) | 0.4 (12.3) | 0.6 (0.4) | |