Table 4.

Mean fentanyl pharmacokinetic parameters after administration of fentanyl citrate IV (50 µg)

Parameter	Cohort 1 q4 h			Cohort 2 q2 h			Cohort 3 q1 h			Cohort 4 q0.5 h
	n	Mean	CV%	n	Mean	CV%	n	Mean	CV%	n	Mean	CV%
Cmax1 (ng/ml)	6	0.337	62.84	6	0.549	40.59	6	0.477	35.25	6	0.369	54.09
Cmax1/D (ng/ml/µg)	6	0.00673	62.84	6	0.0110	40.59	6	0.00955	35.25	6	0.00738	54.09
Tmax1 (h)	6	0.16	101.80	6	0.08	0.00	6	0.08	0.00	6	0.13	50.02
Cmaxn (ng/ml)	6	0.633	14.36	6	0.731	26.84	5	0.893	26.94	6	0.815	18.78
Cmaxn/D (ng/ml/µg)	6	0.0127	14.36	6	0.0146	26.84	5	0.0179	26.94	6	0.0163	18.78
Tmaxn (h)	6	0.08	0.00	6	0.09	7.92	5	0.09	8.62	6	0.09	18.26
AUC0–tau1 (h·ng/ml)	6	0.3298	25.40	6	0.3020	11.27	6	0.2182	25.41	6	0.1093	34.27
AUC0–tau1/D (h·ng/ml/µg)	6	0.00660	25.40	6	0.00604	11.27	6	0.00436	25.41	6	0.00219	34.27
AUC0–taun (h·ng/ml)	6	0.6133	21.55	6	0.6106	18.59	5	0.3964	21.95	6	0.2578	10.19
AUC0–taun/D (h·ng/ml/µg)	6	0.0123	21.55	6	0.0122	18.59	5	0.00793	21.95	6	0.00516	10.19
AUC0–t (h·ng/ml)	6	2.139	26.38	6	2.400	24.23	5	2.211	34.50	6	2.286	17.34
AUC0–t/D (h·ng/ml/µg)	6	0.0143	26.38	6	0.0160	24.23	6	0.0146	31.32	6	0.0152	17.34
AUC0–inf (h·ng/ml)	1	2.882	0.00	5	2.628	28.25	4	2.358	40.07	6	2.517	17.65
AUC0–inf/D (h·ng/ml/µg)	1	0.0192	0.00	5	0.0175	28.25	4	0.0157	40.07	6	0.0168	17.65
t1/2 (h)	1	6.90	0.00	5	5.13	43.75	4	4.69	34.84	6	5.42	17.33
CL (L/h)	1	52.05	0.00	5	61.48	32.25	4	72.29	40.05	6	61.22	18.02
Vz (L)	1	518.2	0.00	5	413.3	28.35	4	439.7	10.99	6	468.4	11.08
${\text{AR}}_{C_{\text{max}}}$	6	3.08	79.40	6	1.57	49.04	5	2.19	57.13	6	2.72	50.85
${\text{AR}}_{{\text{AUC}}_{\text{tau}}}$	6	1.90	18.15	6	2.04	18.10	5	1.89	17.72	6	2.57	33.14

IV intravenous, q every, CV coefficient of variation, C_max1 maximum plasma concentrations after first dose, D dose, T_max1 time of the maximum plasma concentration after first dose, C_maxn maximum plasma concentrations after last dose, T_maxn time of the maximum plasma concentration after last dose, AUC_0–tau1 area under the plasma concentration time curve during the first dosing interval, calculated using the linear-log trapezoidal rule, AUC_0–taun area under the plasma concentration time curve during the last dosing interval, calculated using the linear-log trapezoidal rule, AUC_0–t area under the plasma concentration–time curve from time–zero to the time of the last quantifiable concentration, calculated using the linear-log trapezoidal rule, AUC_0–inf area under the plasma concentration–time curve from time–zero extrapolated to infinity, t_1/2 apparent elimination half-life in the terminal phase by noncompartmental analysis, $A{R}_{C_{\text{max}}}$ accumulation ratio of C_max, $A{R}_{AU{C}_{\mathit{tau}}}$ accumulation ratio of AUC_tau