Alcohol
Medically reviewed by Drugs.com. Last updated on Dec 6, 2021.
What is alcohol?
The term "alcohol" has been synonymous with "spirituous" liquids for the past 300 years. The history of alcohol consumption, along with codes limiting its consumption go back to 1700 B.C. There are four types of alcohol: methyl alcohol, ethyl alcohol, propyl alcohol and butyl alcohol. Ethyl Alcohol, or ethanol (C2H5OH), is the type used in the production of alcoholic beverages. The other three types, methyl, propyl and butyl alcohol, if consumed can result in blindness and death, even in relatively small doses.
Alcohol, or ethanol, is the intoxicating agent found in beer, wine and liquor. Alcohol is produced by fermentation of yeast, sugars, and starches.1 Fruits such as grapes, and grains like barley and wheat are most commonly used for wine, beer and liquors. Other plants, such as the cactus or sugar cane may be used in liquor production.
Fourteen grams or about 0.6 fluid ounces of pure alcohol equals one “drink”. Examples of this amount may include one twelve ounce beer (5 percent alcohol), eight to nine ounces of malt liquor (7 percent alcohol), 5 ounces of wine (12 percent alcohol) or 1.5 fluid ounce “shot” of 80 proof liquor (40 percent alcohol).
In the U.S., The Federal Uniform Drinking Age Act, signed into law in 1984 raised the minimum drinking age to 21 years. All states now prohibit the purchase of alcohol by youth under the age of 21 years since 1988. It is illegal to sell or buy alcohol for anyone under the age of 21. According to The Office of the Surgeon General, alcohol is used by more young people in the United States than tobacco or illicit drugs, resulting in a serious public health concern.2
Alcohol (Ethanol) Pharmacology
Alcohol is a clear, volatile liquid that is highly soluble in water. The absorption of alcohol (ethanol) is decreased by food, especially fatty food. Absorption occurs primarily from the intestine. Alcohol distributes into body water. Blood-alcohol concentration (BAC) is dependent upon weight and body fat, amount and time frame of alcohol consumption, and food effects. Drinking alcohol over shorter time periods or in larger quantities and on an empty stomach will lead to a higher BAC. BAC is usually expressed in grams per deciliter (g/dL). In all 50 U.S. states, 0.08 g/dL would be equal to 0.08 percent BAC, or the legal limit at which one is no longer allowed to drive. Regulations are more strict in many states for drivers less than 21 years of age.
Alcohol is metabolized primarily (90 percent) in the liver. The enzyme alcohol dehydrogenase converts alcohol to acetaldehyde, a sympathomimetic toxin often blamed for the ‘hangover’ effect. Acetaldehyde is further metabolized by aldehyde dehydrogenase to acetic acid, and eventually to carbon dioxide and water. Excretion of small amounts of alcohol also occur through the urine, lungs/breath, and sweat. Alcohol excretion by the lungs constitutes the basis for the Breathalyzer test given by law enforcement who may suspect drinking and driving.
Alcohol elevates the inhibitory neurotransmitter GABA (gamma amino butyric acid) and reduces nerves signals along that neuronal pathway. Because of this action, alcohol is known as a central nervous system (CNS) depressant, and lowers both cognitive and physical capacities. Combination with other CNS depressants, such as opiates...
