There is a perception that has spread widely where people believe that caffeine antagonizes the stimulating alcohol effects. Both alcohol and caffeine have intoxicating effects on the adenosine neurotransmission. Caffeine is a non-selective adenosine receptor antagonist. During excessive alcohol intake, caffeine counteracts the adverse effects of the alcohol which are not wanted. It does so by obstructing the adenosine A1 receptors that channel alcoholic effects such as atactic and sleepy behaviors. On the other hand, the caffeine arousal effects may be counteracted by the alcohol where it induces production of more Adenosine. The caffeine may be used to treat the withdrawal effects of the alcohol basically by inhibiting the production of Adenosine A1 and also the inhibition of the adenosine A2A receptors which contribute to the increasing effects of alcohol. For easier elimination from the body, caffeine metabolizes in three components known as paraxanthine, theobromine, and theophylline (Quarta et al., 2004).
The absorption of caffeine in the human body takes place completely and rapidly. If it is taken orally, it absorption takes place within 45 minutes with the completion rate of 99%. The solubility of caffeine is high such that it diffuses through all tissue and cell membranes where it is taken in all body fluids. It’s crucial to note that neither caffeine nor its components accumulate in the body organs. In fact, 98% of caffeine is excreted from the body through urine. However, as much as the body needs to clear all the caffeine, some factors inhibit it. These factors include age where absorption in infants. The elimination tends to take long as compared to the adults. Other Factors include liver illnesses, use of oral contraceptives, cigarette smoking, and alcohol usage
The absorption of alcohol in the human body is very high and later distributed in the body fluids. It only takes 30 minutes for someone to experiences somnogenic effects. The rate of absorption alcohol in the body differs from person to person as it is noted that absorption to the female takes place much quicker than to the male. Also, the presence of food in the digestive tract slows the rate of absorption. However, the effects of the alcohol effects depend on various factors which include sex, the habit of taking alcohol, caffeine and many others.
According to El Yacoubi, et al., (2003), in the human body, the caffeine generates the same level of pharmacological effects as psycho-stimulants like heroin and cocaine. It results in increasing arousal effects, reinforcing effects, and motor activity. However, the caffeine has low arousal effects as compared to the psycho-stimulants. To maintain the same level of psycho-stimulation, the caffeine user has to continuously depend on its intake. It is important to note, that there is a small difference between the wanted effects of psycho-stimulants and unwanted effects of caffeine especially the anxiety. Alcohol on the hand is the psychostimulant and usually has withdrawal and ataxic effects. It results to slowing motor activities and reinforcing effects. As it happens with caffeine, there is a narrow gap between ‘wanted’ effects of alcohol such as reinforcing effects and ‘unwanted’ effects such as withdrawal and atactic effect. It’s quite evident that alcohol and caffeine can be used as drugs for counteracting each other unwanted effects.
Caffeine is a non-selective competitive adenosine receptor antagonist, and it releases its psycho-stimulant effects by antagonizing the tonic effects of endogenous adenosine on central receptors. This is achieved by the ability of the adenosine to regulate the activity of the ascending central neurotransmitters which are responsible for arousal effects. The reinforcing effect of the caffeine originates from striatal A1 and A2A receptors. Conversely, there are many pharmacological effects of alcohol, as its multitude of neurotransmitter receptors that are highly distributed in the brain. Alcohol potentiates the GABAergic neurotransmission through the facilitation of GABA receptors. It also inhibits glutamatergic neurotransmission through acting on the ionotropic receptors. The facilitation of GABAergic neurotransmission and inhibition of glutamatergic transmission are the cause of depressant effects of alcohol (Quarta et al., 2004).