Table 1.

Pharmacokinetic parameter of yohimbine 5 mg 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 5 mg (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 (ng/mL)	17.5a,d	9.14–33.3	69.2a	54.9–87.3	59.5d	34.6–102	53.2a	42.2–66.9
tmax (h)e	0.36a,b	0.28–0.49	0.42a	0.33–0.56	0.42	0.31–0.65	0.40a	0.28–0.68
AUC (ng/mL*h)	16.2a,b,d	8.93–29.5	480	418–550	109a,d	48.7–24.2	551	470–645
t1/2 (h)	0.64a,d	0.55–0.74	13.25a	11.8–14.9	1.24a,d	0.91–1.70	15.5	13.8–17.5
Vss/F (L)	313a,d	166–589			18.3d	9.40–35.6
Cl/F (mL/min)	5130a,b,w	2821–9330			768a,d	344–1711
MR AUC	0.03a,b,d	0.02–0.06			0.20a,d	0.10–0.40
IM	(n = 2)				(n = 2)
Cmax (ng/mL)	52.9	1.76–1592	37.4c	15.1–92.6	107	5.66–2035	24.6	0.005–112,113
tmax (h)e	0.75b		0.75c		0.71		1.05
AUC (ng/mL*h)	78.7b,c	16.5–375	376	78.8–1795	488	37.6–6325	436	201–947
t1/2 (h)	0.96c,d	0.05–18.5	14.8	4.6–48.2	2.86d	0.05–172	14.86	0.008–2550
Vss/F (L)	115	3.34–3946			59.6	2.45–1448
Cl/F (mL/min)	1059b,c	222–5047			171	13.2–2218
MR AUC	0.21b,c	0.21–0.21			1.12	0.04–31.5
PM	(n = 4)				(n = 2)
Cmax (ng/mL)	198a	121–327	12.0a,c	4.56–31.6	151	12.2–1864	12.7a	0.33–485
tmax (h)e	1.42	0.97–2.64	6.67a,c	4.93–10.3	1.54		5.46a
AUC (ng/mL*h)	2044a,c	1073–3895	584	135–2528	1410a	409–4861	427	290–628
t1/2 (h)	6.59a,c	5.20–8.35	31.2a	11.5–84.7	5.95a	2.78–12.7	21.16	0.72–619
Vss/F (L)	24.5a	14.8–40.7			203	124–334
Cl/F (mL/min)	40.8a,c	21.4–77.7			59.1a	17.41–204
MR AUC	3.50a,c	0.63–19.5			3.3a	1.42–7.75

AUC area under the plasma concentration–time curve, CI confidence interval, Cl/F apparent oral clearance, C_max maximum plasma concentration, EM extensive metaboliser, Geom. mean geometric mean, IM intermediate metaboliser, MR AUC metabolic AUC ratio (AUC yohimbine/AUC 11-OH-yohimbine), PM poor metaboliser, st_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