Coffee and caffeine and alcohol effects on psychomotor function.

Interactions of alcohol and caffeine were studied in two double-blind and crossover trials in which several psychophysiologic functions and subjective effects were measured in healthy men. The effects of alcohol (1 gm/kg) with and without caffeine (200 or 500 mg) were measured in 10 subjects. Two doses (0.7 or 1.5 gm/kg) of alcohol alone and in combination with caffeine (250 + 250 mg) were similarly studied in another 10 subjects. Alcohol impaired psychomotor functions to an extent dependent on dose whereas caffeinated and decaffeinated coffee did not. Both kinds of coffee also failed to modify alcohol effects. Subjectively, caffeine was indistinguishable from placebo and no particular interaction of alcohol and caffeine was detected. Alcohol did elevate serum caffeine concentrations. We conclude that coffee does not counteract alcohol inebriation.