Caffeine Reversal of Ethanol Effects on the Multiple Sleep Latency Test, Memory, and Psychomotor Performance

Abstract

Caffeine has been shown to reverse some of the performance-impairing effects of ethanol. However, it is not known whether this antagonistic effect of caffeine is mediated by a reduction in sleepiness. The present study assessed physiological alertness/sleepiness, memory, and psychomotor performance following the administration of placebo, ethanol, and caffeine+ethanol combinations. A total of 13 healthy individuals (21-35 years old) underwent four conditions presented in a Latin Square Design: placebo-placebo, ethanol (0.5 g/kg)-placebo, ethanol (0.5 g/kg)-caffeine 150 mg, and ethanol (0.5 g/kg)-caffeine 300-mg. The Multiple Sleep Latency Test (MSLT), psychomotor performance battery, memory test, and mood/sleepiness questionnaires were administered following each condition. The peak breadth ethanol concentration (BrEC) was 0.043+/-0.0197% and did not differ among the three caffeine treatments. As expected, ethanol reduced mean latency on the MSLT. The lowest caffeine dose reversed this effect and the highest dose increased mean latency (greater alertness) significantly beyond placebo levels. Ethanol also impaired psychomotor performance and memory. The 300-mg caffeine dose restored performance and memory measures to placebo levels. Although visual analog ratings of dizziness were increased by ethanol, they were not diminished by either caffeine dose. In conclusion, Low-dose caffeine prevented the sleepiness and performance impairment associated with a moderate dose of ethanol. Thus, caffeine, similar to other stimulants, can reverse the physiologically sedating effects of ethanol, although other negative effects remain.

Activation of Adenosine A1 Receptors Reduces Anxiety-Like Behavior During Acute Ethanol Withdrawal (Hangover) in Mice

“…Acute exposure to ethanol inhibits adenosine re-uptake via a facilitative nucleoside transporter, increasing the extracellular concentration of adenosine (Nagy et al, 1990;Krauss et al, 1993). In humans, the nonselective adenosine receptor antagonist caffeine reduces sleepiness and psychomotor performance impairment produced by moderate-to-high ethanol doses (Franks et al, 1975;Fillmore and Vogel-Sprott, 1995;Liguori and Robinson, 2001;Drake et al, 2003). In rodents, adenosine receptors seem to modulate some of the pharmacological properties of ethanol, such as sedative/ hypnotic effects (El Yacoubi et al, 2003), motor incoordination (Meng and Dar, 1995;Barwick and Dar, 1998;Dar, 2001), and development of rapid tolerance to ethanolinduced motor impairments (Batista et al, 2005).…”

“…Acute exposure to ethanol increases the concentration of extracellular adenosine (Nagy et al, 1990;Krauss et al, 1993). Moreover, there is considerable evidence that the co-administration of caffeine (a nonselective adenosine receptor antagonist) can reduce sleep and psychomotor performance impairment associated with moderate-to-high ethanol doses in humans (Franks et al, 1975;Fillmore and Vogel-Sprott, 1995;Liguori and Robinson, 2001;Drake et al, 2003). Furthermore, the combined administration of caffeine and alcohol can increase the development of alcohol tolerance (Fillmore, 2003).…”

Caffeine Effects on Sleep Taken 0, 3, or 6 Hours before Going to Bed

“…[1][2][3][4][5][6][7] Up to 500 mg of caffeine can be found in commercially available 16-oz servings of brewed coffee. 8 The use of similarly high doses of caffeine-containing beverages, including energy drinks has led to a doubling of caffeine-related emergency department visits from 2007-2011.…”

Ethanol Interference on Adenosine System

“…This reinforcement is in part mediated via A 2A R activation and probably associated with intracellular A 2 activation of cAMP/PKA signalling cascades in the nucleus accumbens (Thorsell, et al, 2007;Adams et al, 2008), but the exact mechanism of action remains unclear. Studies in humans examining methylxanthine and ethanol interactions have mostly focused on the influence that caffeine exerts on ethanol intoxication, and have yielded mixed results (Liguori and Robinson 2001;Drake et al 2003); but a point that needs further attention is the fact that these studies converge upon the point that caffeine consumed in association with ethanol, rather than improving ethanol-induced impairments, would reduce the self-perception of ethanol intoxication (Morelli & Simola, 2011), since human data also show that caffeine enhances tolerance to ethanol (Fillmore, 2003).…”