TABLE 2.
Rifampin pharmacokinetics parameter estimates among 100 newly diagnosed sputum-smear-positive TB patients
| Parameter description or variability | Typical value |
|
|---|---|---|
| Estimate | 90% CI | |
| Description (abbreviation) | ||
| Clearance on day 7a (CLday7) (liters/h) | 13.9 | 12.7; 15.0 |
| Clearance at steady statea (CLSS) (liters/h) | 16.5 | 15.0; 18.0 |
| Induction half-life (t1/2) (days) | 6 FIXED | NAb |
| Vol of distribution (V) (liters) | 55.8 | 51.4; 60.1 |
| Absorption rate constant (ka) (1/h) | 1.77 | 1.41; 2.34 |
| Absorption mean transit time (MTT) (h) | 1.50 | 1.35; 1.66 |
| No. of absorption transit compartment (NN) | 27.6 | 19.5; 46.7 |
| Bioavailability (BIO) | 1 FIXED | NA |
| % change in bioavailability for HIV+, no supplementation (+%) | −21.8 | −31.5; −10.3 |
| % change in bioavailability for HIV+, with supplementation (+%) | −13.3 | −22.1; −2.1 |
| % change in patients during the continuation phase of treatment (+%) | 13.7 | 3.5; 23.8 |
| % change in MTT (+%) and −ka (−%) in patients on supplementation | 26.9 | 14.0; 41.6 |
| Proportional error (%) | 13.7 | 11.6; 15.7 |
| Additive error (μg/ml) | 0.0417 | 0.0147; 0.0994 |
| Variability | ||
| Between-subject variability of clearance (%CV) | 24.0 | 18.3; 29.1 |
| Between-occasion variability of absorption rate constant (%CV) | 67.6 | 51.8; 85.5 |
| Between-occasion variability of mean transit time (%CV) | 34.0 | 25.1; 41.6 |
| Between-occasion variability of bioavailability (%CV) | 31.1 | 25.7; 35.5 |
| MTT-BIO correlation (%) | −25.2 | −44.7; 1.6 |
a
Steady state was estimated to last about 30 days or more.
b
NA, not applicable.