Table 2.

Pharmacokinetic parameter of yohimbine 50 µg and its metabolite 11-OH-yohimbine after a single oral dose and during treatment with paroxetine 20 mg stratified according to the cytochrome P450 2D6 genotype

	Yohimbine 50 µg (n = 10)				+ Paroxetine 20 mg (n = 10)
	Yohimbine		11-OH-yohimbine		Yohimbine		11-OH-yohimbine
	Geom. mean	95% CI	Geom. mean	95% CI	Geom. mean	95% CI	Geom. mean	95% CI
EM
Cmax (pg/mL)	73.9a,b,d	35.4–154	446a,d	342–581	249d	129–481	848a,d	732–983
tmax (h)e	0.36a	0.28–0.49	0.43	0.31–0.70	0.42	0.31–0.65	0.42	0.31–0.69
AUC (pg/mL*h)	74.7a,b,d	36.1–155	4374d	3621–5283	290a,b,d	176–479	15,649d	9106–26,894
t1/2 (h)	0.68a,b,d	0.58–0.80	16.0a	13.42–19.2	1.29a,d	0.98–1.70	20.22	13.8–29.6
Vss/F (L)	810a,b,d	421–1558			231a,d	124–430
Cl/F (mL/min)	11,152a,b,d	5381–23,115			2066a,d	869–4911
MR AUC	0.02a,b	0.01–0.05			0.04a	0.02–0.06
IM	(n = 2)				(n = 2)
Cmax (pg/mL)	266b,c	58.8–1197	277c	123–628	815	126–5253	566	223–1439
tmax (h)+	0.75c		1.0		0.71		0.60
AUC (pg/mL*h)	456b,c	374–556	4216	2064–8614	2588b	113–59,583	14,066c	48.4–4,089,742
t1/2 (h)	1.33b,c	0.94–1.90	19.1	6.62–54.9	2.50	0.04–164.8	24.0	0.24–2363
Vss/F (L)	226b,c	18.8–2730			83.0	54.0–128
Cl/F (mL/min)	1829b,c	1500–2231			322	14.0–7411
MR AUC	0.10a	0.05–0.19			0.24	0.19–0.30
PM	(n = 4)				(n = 2)
Cmax (pg/mL)	2188a,c	965–4963	83.8a,c,d	42.0–167.2	1392	563–3444	395a,d	37.2–4195
tmax (h)e	1.42a,c	0.97–2.64	7.27a,c	4.44–20.1	1.54		8.00a,c
AUC (ng/mL*h)	15,274a,c	9427–24,745	4402d	2165–8948	12,229a	4946–30,237	20,276d	1.88–2,191,230
t1/2 (h)	5.85a,c	5.57–6.14	34.71a	13.0–92.7	5.55a	2.53–12.2	33.7	0.04–30,114
Vss/F (L)	28.4a,c	16.7–48.4			36.9a	11.8–116
Cl/F (mL/min)	54.6a,c	33.7–88.4			68.1a	27.6–169
MR AUC	3.53a,c	2.11–5.90			3.66a	0.61–21.84

AUC area under the plasma concentration–time curve, CI confidence interval, Cl/F apparent oral clearance, C_max maximum plasma concentration, IM intermediate metaboliser, EM extensive metaboliser, Geom. mean geometric mean, MR AUC metabolic AUC ratio (AUC yohimbine/AUC 11-OH-yohimbine), PM poor metaboliser, t_max time to reach maximum plasma concentration, t_1/2 terminal elimination half-life, V_ss/F volume of distribution at steady state, p < 0.05

^aEM vs PM

^bEM vs IM

^cPM vs IM

^dWithout vs with paroxetine (repeated measures)

^eHarmonic mean