Table 1.

Pharmacokinetic parameters of caffeine following a single administration of the coffee enema or the oral coffee consumption (n = 11).

Parameters	Coffee procedure				95% confidence   interval of the difference		P value*
	Coffee enema	Oral coffee consumption	Mean difference	Standard error difference	Lower	Upper
C max⁡  (μg/mL)	0.77 ± 0.14	2.47 ± 0.39	−1.70	0.12	−1.96	−1.44	<0.001
AUC0–12  (μg·h/mL)	3.69 ± 0.95	13.05 ± 2.06	−9.36	0.71	−10.83	−7.89	<0.001
AUC0–∞  (μg·h/mL)	4.73 ± 1.74	16.32 ± 3.89	−11.59	1.28	−14.27	−8.84	<0.001
T max⁡ (h)	0.30 ± 0.12	0.44 ± 0.11	−0.14	0.05	−0.24	−0.02	0.02
t 1/2 (h)	4.68 ± 1.36	4.87 ± 1.39	−0.19	0.59	−1.41	1.04	0.76

Data represents mean ± SD. Abbreviations: C _max⁡: maximum plasma caffeine concentrations, AUC_0–12: area under the concentration-time curve from administration to 12 hours, AUC_0–∞: area under the concentration-time curve from administration and extrapolation to infinity, T _max⁡: time to reach maximum plasma concentration, and t _1/2: half-life. *Statistical analysis using paired Student's t-test.