Table 2.

Intravenous and oral alfentanil pharmacokinetic parameters

	Control	Acme ritonavir	Sieauy-siaie Ritonavir
IV alfentanil
Cmax (ng/ml)	115 ± 32		28 ± 5a
Cmax/dose (ng/ml/mg)	109 ± 40		78 ± 17 a
AUC0-∞ (ng •hr •ml−1)	73 ± 25		86 ± 26
AUC0-∞/dose (ng•hr•ml−1/mg)	67 ± 23		237±62a
AUC0-∞/dose ratio (ritonavir/control)			3.6 (2.8, 4.7)
CLIV (ml•kg−1•min−1)	3.91 ± 1.59		1.05 ± 0.28 a
Elimination t1/2 (hr)	1.1 ± 0.2		4.9 ± 1.2 a
EH	0.26 ± 0.10		0.07 ± 0.02 a
Oral alfentanil
Cmax (ng/ml)	43 ± 17	15 ± 5 a	12 ± 3 a
Cmax/dose (ng/ml/mg)	14 ± 5	46 ± 14 a	38 ± 9 a b
AUC0-∞ (ng •hr •ml−1)	78 ± 36	182±48a	74 ± 21
AUC0-∞/dose (ng•hr•ml−1/mg)	25 ± 9	573 ±107a	236±62ab
AUC0-∞/dose ratio (ritonavir/control)		24.8 (15.2, 40.4)	10.0 (6.7, 15.1)
CL/F (ml•kg−1•min−1)	11.5 ± 6.3	0.4 ± 0.1 a	1.1 ± 0.3 a b
Elimination t1/2 (hr)	1.1 ± 0.3	12.1 ± 1.7 a	6.1 ± 2.9 a b
Foral	0.37 ± 0.08		0.95 ± 0.08 a
EG	0.51 ± 0.12		0.00 ± 0.08 a

Subjects received 15 and 5 μg/kg IV ALF at the control and ritonavir sessions, respectively, and 43 and 4.3 μg/kg oral ALF at the control and ritonavir sessions, respectively. One subject received 15 μg/kg IV ALF and 43 μg/kg oral ALF at control and ritonavir sessions, and was omitted from the analysis of ALF pharmacokinetics. C_max and AUC are shown normalized to dose. All other variables are not dose adjusted. Results are the arithmetic mean ± SD (n=11), except the AUC_0-∞/dose ratio (ritonavir/control), which is the geometric mean (90% CI).

^aSignificantly different from control (p<0.05)

^bSignificantly different from acute ritonavir (p<0.05)