What Is Ethanol Toxicity?

Acute ethanol toxicity — also known as alcohol poisoning, alcohol toxicity or ethanol poisoning — is the result of overconsumption of ethyl alcohol beyond the ability of the body to metabolize it. Alcohol begins to be absorbed as soon as orally ingested, beginning in the mouth and continuing through the esophagus, stomach and small intestine to reach almost full absorption and concentration in the bloodstream within 15 to 30 minutes. As is widely known by the general public, ethyl alcohol metabolism takes place primarily in the liver. When the rate of alcohol ingestion surpasses the ability of the liver to metabolize it, the blood alcohol concentration increases and an individual becomes drunk or intoxicated. From a medical standpoint and physiological perspective, ethanol toxicity begins with intoxication.

When alcohol reaches the bloodstream, it easily passes the blood-brain barrier, hijacks the brain's gamma-amino butyric acid (GABA) system and results in a pleasant feeling of relaxation and mild euphoria. With another drink or two, further increases in blood alcohol concentrations dampen the individual's usual behavioral inhibitions and impair cognitive judgments about what does and does not constitute reasonable behavior. These behavioral changes occur secondary to increased blood alcohol levels beyond the ability of the body to metabolize and are symptomatic of physiological alcohol poisoning. One of the usual behavioral inhibitions overcome at this point is whether or not to continue drinking.

A growing lack of physical coordination, slurring of speech and difficulty balancing are additional symptoms of alcohol poisoning. At this point, the sedative properties of ethyl alcohol will have progressed from a feeling of relaxation to intense sleepiness and finally, loss of consciousness. Continued sedation — from drinks ingested between physiological ethanol toxicity and intoxication until loss of consciousness — results in depression of the brain's respiratory control and function. An intoxicated person's respiratory rate will slow and become irregular. Respiratory depression sadly sometimes progresses to a complete cessation of breathing and subsequent death.

When an intoxicated person in some stage of acute alcohol poisoning stops drinking, the liver eventually catches up with its backlog of ethyl alcohol metabolism. As the bloodstream is slowly cleared of ethanol, the body is left with an abundance of acetaldehyde, a compound halfway between metabolism of ethyl alcohol into water and carbon dioxide. Acetaldehyde is considered to be one of the primary culprits in another symptom of recent ethanol toxicity: the hangover. Another reason for hangover symptoms is the dehydration that results from alcohol poisoning.