Table 3.

Alcohol and Caffeine Pharmacokinetic Parameters and Statistical Analysis for Comparison Between Conditions with Ethanol (A/RB vs A) and Conditions with Caffeine (A/RB vs RB)

Outcome	Parameters	Values
		A/RB	Alcohol	P
Alcohol plasma	Cmax (µmol/mL)	18.2 ± 3.7	15.3 ± 2.2	**
	tmax (h)	2.0 (1.5–2.5)	1.8 (1.5–2.5)	N.S.
	AUC0-8h (µmol.h/mL)	64.1 ± 17.1	54.6 ± 17.6	**
	Elimination rate (µmol/mL/h)	2.6 ± 0.7	2.7 ± 0.7	N.S.
		A/RB	RB	P
Caffeine plasma	Cmax (nmol/mL)	20.4 ± 2.9	17.6 ± 3.4	*
	tmax (h)	2.0 (1.5–6.0)	2.0 (1.5–4.0)	N.S.
	AUC0-8h (nmol.h/mL)	111.9 ± 21.8	90.3 ± 20.2	**
	t  1/2 (h)	5.8 ± 2.8	5.4 ± 2.3	N.S.
Caffeineu	Excretion 0–8h (nmol)	32449.7 ± 10012.5	21568.6 ± 7262.1	**
Paraxanthineu	Excretion 0–8h (nmol)	22531.8 ± 11004.6	40048.8 ± 16722.5	**
Theobromineu	Excretion 0–8h (nmol)	13734.4 ± 4436.5	10785.3 ± 5123.6	N.S.
Theophyllineu	Excretion 0–8h (nmol)	405.0 ± 237.0	1460.2 ± 1587.0	*
17X/137X ratiou	Excretion 0–4h	0.3 ± 0.1	0.9 ± 0.6	***
17X/137X ratiou	Excretion 4–8h	4.2 ± 2.3	6.4 ± 3.5	***
17X/137X ratiou	Excretion 0–8h	0.7 ± 0.4	2.0 ± 1.0	***

Abbreviations: Alcohol, alcohol + placebo RB; A/RB, alcohol + Red Bull; AUC, area under the curve; C_max, peak concentration; P, placebo alcohol + placebo RB; RB, Red Bull + placebo alcohol; t_max, time to reach peak concentrations; t_1/2, half-life; U, urine; 17X/137X, paraxanthine/caffeine ratio. Values are mean ± SD except for t_max (median, minimum and maximum). Paired Student’s t test: N.S. mean not significant; * P < .05; ** P < .01; *** P < .001. Amount of 18.2 µmol/mL of alcohol corresponds to 83.5 mg/dL and 15.3 µmol/mL to 70.5 mg/dL.