TABLE 2.

Steady-state pharmacokinetics of rifampin and desacetylrifampin^a

Parameter	Value 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
AUC0-24	0.17 (0.10-0.25)	0.13 (0.08-0.20)	1.26 (1.09-1.45)	0.002c
Cmax	0.14 (0.07-0.22)	0.11 (0.05-0.19)	1.23 (1.03-1.48)	0.024c

^aAfter 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).

^bCI, confidence interval.

^cIndependent t test on log-transformed data.

^dPearson chi-square test.

^eWilcoxon rank sum test.