TABLE 2.

Steady-state pharmacokinetics of rifampin and desacetylrifampina

ParameterValue at rifampin dose (mg):600-mg/450-mg ratio (geometric mean + 95% CIb)P value
600 (n = 23)450 (n = 24)
Rifampin
    AUC0-24 (mg·h/liter)79.7 (38.7-138.1)48.5 (26.7-72.8)1.65 (1.38-1.96)<0.001c
    Cmax (mg/liter)15.6 (5.1-26.6)10.5 (6.2-16.6)1.49 (1.22-1.81)<0.001c
    Cmax >8 mg/liter [no. (%)]22/23 (96)19/24 (79)0.090d
    Tmax (h) [median (range)]1 (1-6)2 (1-4)0.428e
    t1/2 (h)2.2 (1.3-6.3)1.9 (1.5-5.2)1.13 (0.95-1.35)0.176c
    CL/F (liter/h)7.5 (4.3-15.5)9.2 (6.1-16.8)0.82 (0.69-0.97)0.021c
    V/F (liters)23.3 (12.3-96.1)25.3 (12.9-55.7)0.92 (0.72-1.18)0.502c
Desacetylrifampin
    AUC0-24 (mg·h/liter)13.2 (7.2-25.6)6.4 (2.3-13.3)2.07 (1.61-2.65)<0.001c
    Cmax (mg/liter)2.2 (0.6-3.9)1.2 (0.5-2.6)1.83 (1.40-2.41)<0.001c
    Tmax (h) [median (range)]4 (1.5-6)4 (1.5-4)0.586e
    t1/2 (h)2.5 (1.7-9.9)3.2 (2.0-18.9)0.80 (0.63-1.03)0.085c
Desacetyrifampin/rifampin ratio
    AUC0-240.17 (0.10-0.25)0.13 (0.08-0.20)1.26 (1.09-1.45)0.002c
    Cmax0.14 (0.07-0.22)0.11 (0.05-0.19)1.23 (1.03-1.48)0.024c
  • a After daily administration of a high (600-mg; 13-mg/kg) or standard (450-mg; 10-mg/kg) dose of rifampin (geometric mean plus range, unless stated otherwise).

  • b CI, confidence interval.

  • c Independent t test on log-transformed data.

  • d Pearson chi-square test.

  • e Wilcoxon rank sum test.