Table 1: Pharmacokinetic parameters of caffeine following a single administration of the coffee enema or the oral coffee consumption ( ).

ParametersCoffee procedure    95% confidence
  interval of the difference
value*
Coffee enemaOral coffee consumption Mean difference Standard error differenceLowerUpper

  (μg/mL) −1.70 0.12 −1.96−1.44<0.001
  (μg·h/mL) −9.36 0.71 −10.83−7.89<0.001
  (μg·h/mL) −11.59 1.28 −14.27−8.84<0.001
 (h) −0.14 0.05 −0.24−0.020.02
 (h) −0.19 0.59 −1.41 1.04 0.76

Data represents mean ± SD. Abbreviations: : maximum plasma caffeine concentrations, : area under the concentration-time curve from administration to 12 hours, : area under the concentration-time curve from administration and extrapolation to infinity, : time to reach maximum plasma concentration, and : half-life. *Statistical analysis using paired Student’s -test.