Alcohol intoxication, also known as drunkenness among other names, is a physiological condition that may result in psychological alterations of consciousness. Symptoms of alcohol intoxication include euphoria, flushed skin, and decreased social inhibition at lower doses, with larger doses producing progressively severe impairments of balance, and decision-making ability as well as nausea or vomiting from alcohol's disruptive effect on the semicircular canals of the inner ear and chemical irritation of the gastric mucosa. Extreme levels of blood-borne alcohol may result in coma or death.
Alcohol intoxication is the result of drinking alcohol such that it enters the bloodstream faster than it can be metabolized by the body. Metabolism results in breaking down the ethanol into non-intoxicating byproducts.
Some effects of alcohol intoxication, such as euphoria and lowered social inhibition, are central to alcohol's desirability as a beverage. Throughout history it has been one of the world's most widespread recreational drugs. Despite this widespread use and alcohol's legality in most countries, many medical sources tend to describe any level of alcohol intoxication as a form of poisoning due to ethanol's damaging effects on the body in large doses. Some religions consider alcohol intoxication to be a sin.
Acute alcohol poisoning is a related medical term used to indicate a dangerously high concentration of alcohol in the blood, high enough to induce coma, respiratory depression, or even death. It is considered a medical emergency. The term is mostly used by healthcare providers. Toxicologists use the term "alcohol intoxication" to discriminate between alcohol and other toxins.
The signs and symptoms of acute alcohol poisoning include:
Alcohol is metabolized by a normal liver at the rate of about 8 grams of pure ethanol per hour. 8 grams or 10 ml (0.34 US fl oz) is one British standard unit. An "abnormal" liver with conditions such as hepatitis, cirrhosis, gall bladder disease, and cancer is likely to result in a slower rate of metabolism. 
Ethanol is metabolised to acetaldehyde by alcohol dehydrogenase (ADH), which is found in many tissues, including the gastric mucosa. Acetaldehyde is metabolised to acetate by acetaldehyde dehydrogenase (ALDH), which is found predominantly in liver mitochondria. Acetate is used by the muscle cells to produce acetyl-CoA using the enzyme acetyl-CoA synthetase, and the acetyl-CoA is then used in the citric acid cycle.
Ethanol's acute effects are due largely to its nature as a central nervous system depressant, and are dependent on blood alcohol concentrations:
As drinking increases, people become sleepy, or fall into a stupor. After a very high level of consumption, the respiratory system becomes depressed and the person will stop breathing. Comatose patients may aspirate their vomit (resulting in vomitus in the lungs, which may cause "drowning" and later pneumonia if survived). CNS depression and impaired motor co-ordination along with poor judgment increases the likelihood of accidental injury occurring. It is estimated that about one-third of alcohol-related deaths are due to accidents and another 14% are from intentional injury.
In addition to respiratory failure and accidents caused by effects on the central nervous system, alcohol causes significant metabolic derangements. Hypoglycaemia occurs due to ethanol's inhibition of gluconeogenesis, especially in children, and may cause lactic acidosis, ketoacidosis, and acute renal failure. Metabolic acidosis is compounded by respiratory failure. Patients may also present with hypothermia.
In the past, alcohol was believed to be a non-specific pharmacological agent affecting many neurotransmitter systems in the brain. However, molecular pharmacology studies have shown that alcohol has only a few primary targets. In some systems, these effects are facilitatory and in others inhibitory.
Among the neurotransmitter systems with enhanced functions are: GABAA,5-HT3 receptor agonism (responsible for GABAergic (GABAA receptor PAM), glycinergic, and cholinergic effects), nicotinic acetylcholine receptors.
The result of these direct effects is a wave of further indirect effects involving a variety of other neurotransmitter and neuropeptide systems, leading finally to the behavioural or symptomatic effects of alcohol intoxication.
Many of the effects of activating GABAA receptors have the same effects as that of ethanol consumption. Some of these effects include anxiolytic, anticonvulsant, sedative, and hypnotic effects, cognitive impairment, and motor incoordination. This correlation between activating GABAA receptors and the effects of ethanol consumption has led to the study of ethanol and its effects on GABAA receptors. It has been shown that ethanol does in fact exhibit positive allosteric binding properties to GABAA receptors. However, binding is only limited to pentamers containing the ?-subunit rather than the ?-subunit. GABAA receptors containing the ?-subunit have been shown to be located exterior to the synapse and are involved with tonic inhibition rather than its ?-subunit counterpart, which is involved in phasic inhibition. The ?-subunit has been shown to be able to form the allosteric binding site which makes GABAA receptors containing the ?-subunit more sensitive to ethanol concentrations, even to moderate social ethanol consumption levels (30mM). While it has been shown by Santhakumar et al. that GABAA receptors containing the ?-subunit are sensitive to ethanol modulation, depending on subunit combinations receptors, could be more or less sensitive to ethanol. It has been shown that GABAA receptors that contain both ? and ?3-subunits display increased sensitivity to ethanol. One such receptor that exhibits ethanol insensitivity is ?3-?6-? GABAA. It has also been shown that subunit combination is not the only thing that contributes to ethanol sensitivity. Location of GABAA receptors within the synapse may also contribute to ethanol sensitivity.
There are also various models of breathalyzer units that are available for consumer use. Because these may have varying reliability and may produce different results than the tests used for law-enforcement purposes, the results from such devices should be conservatively interpreted.
Many informal intoxication tests exist, which, in general, are unreliable and not recommended as deterrents to excessive intoxication or as indicators of the safety of activities such as motor vehicle driving, heavy equipment operation, machine tool use, etc.
For determining whether someone is intoxicated by alcohol by some means other than a blood-alcohol test, it is necessary to rule out other conditions such as hypoglycemia, stroke, usage of other intoxicants, mental health issues, and so on. It is best if his/her behavior has been observed while the subject is sober to establish a baseline. Several well-known criteria can be used to establish a probable diagnosis. For a physician in the acute-treatment setting, acute alcohol intoxication can mimic other acute neurological disorders, or is frequently combined with other recreational drugs that complicate diagnosis and treatment.
Acute alcohol poisoning is a medical emergency due to the risk of death from respiratory depression or aspiration of vomit if vomiting occurs while the person is unresponsive. Emergency treatment strives to stabilize and maintain an open airway and sufficient breathing, while waiting for the alcohol to metabolize. This can be done by removal of any vomitus or, if the person is unconscious or has impaired gag reflex, intubation of the trachea.
Other measures may include
A normal liver detoxifies the blood of alcohol over a period of time that depends on the initial level and the patient's overall physical condition. An abnormal liver will take longer but still succeeds, provided the alcohol does not cause liver failure.
A person consuming a dangerous amount of alcohol persistently can develop memory blackouts and idiosyncratic intoxication or pathological drunkenness symptoms.
Long-term persistent consumption of excessive amounts of alcohol can cause liver damage and have other deleterious health effects.
Alcohol intoxication is a risk factor in some cases of catastrophic injury, in particular for unsupervised recreational activity. A study in the province of Ontario based on epidemiological data from 1986, 1989, 1992, and 1995 states that 79.2% of the 2,154 catastrophic injuries recorded for the study were preventable, of which 346 involved alcohol consumption. The activities most commonly associated with alcohol-related catastrophic injury were snowmobiling (124), fishing (41), diving (40), boating (31) and canoeing (7), swimming (31), riding an all-terrain vehicle (24), and cycling (23). These events are often associated with unsupervised young males, often inexperienced in the activity, and many result in drowning. Alcohol use is also associated with unsafe sex.
Laws on drunkenness vary. In the United States, it is a criminal offense for a person to be drunk while driving a motorized vehicle, except in Wisconsin, where it is only a fine for the first offense. It is also a criminal offense to fly an aircraft or (in some American states) to assemble or operate an amusement park ride while drunk. Similar laws also exist in the United Kingdom and most other countries.
In some countries, it is also an offense to serve alcohol to an already-intoxicated person, and, often, alcohol can be sold only by persons qualified to serve responsibly through alcohol server training.
The blood alcohol content (BAC) for legal operation of a vehicle is typically measured as a percentage of a unit volume of blood. This percentage ranges from 0.00% in Romania and the United Arab Emirates; to 0.05% in Australia, South Africa, Germany, Scotland and New Zealand (but 0.00% for under 20 year olds); to 0.08% in England and Wales, the United States and Canada.
The United States Federal Aviation Administration prohibits crew members from performing their duties with a BAC greater than 0.04% within eight hours of consuming an alcoholic beverage, or while under the influence of alcohol.
In some countries, there are special facilities, sometimes known as "drunk tanks", for the temporary detention of persons found to be drunk.
Some religious groups permit the consumption of alcohol. Some permit consumption but prohibit intoxication, while others prohibit alcohol consumption altogether. Many Christian denominations such as Catholic, Orthodox, and Lutheran use wine as a part of the Eucharist and permit the drinking of alcohol but consider it sinful to become intoxicated.
In the Bible, the book of Proverbs contains several chapters dealing with the bad effects of drunkenness and warning to stay away from intoxicating beverages. The book of Leviticus tells of Nadav and Avihu, Aaron the Priest's eldest sons, who were killed for serving in the temple after drinking wine, presumably while intoxicated. The book continues to discuss monasticism where drinking wine is prohibited. The story of Samson in the Book of Judges tells of a monk from the tribe of Dan who is prohibited from cutting his hair and drinking wine. Romans 13:13-14, 1 Corinthians 6:9-11, Galatians 5:19-21, and Ephesians 5:18 are among a number of other Bible passages that speak against drunkenness. While Proverbs 31:4, warns against kings and rulers drinking wine and strong drink, Proverbs 31:6-7 promotes giving strong drink to the perishing and wine to those whose lives are bitter, to forget their poverty and troubles.
Some Protestant Christian denominations prohibit the drinking of alcohol based upon Biblical passages that condemn drunkenness, but others allow moderate use of alcohol. In some Christian groups, a small amount of wine is part of the rite of communion.
In The Church of Jesus Christ of Latter-day Saints, alcohol consumption is forbidden, and teetotalism has become a distinguishing feature of its members. Jehovah's Witnesses allow moderate alcohol consumption among its members.
In the Qur'an, there is a prohibition on the consumption of grape-based alcoholic beverages, and intoxication is considered as an abomination in the Hadith. Islamic schools of law (Madh'hab) have interpreted this as a strict prohibition of the consumption of all types of alcohol and declared it to be haraam ("forbidden"), although other uses may be permitted.
In Buddhism, in general, the consumption of intoxicants is discouraged for both monastics and lay followers. Many followers of Buddhism observe a code of conduct known as the Five Precepts, of which the fifth precept is an undertaking to refrain from the consumption of intoxicating substances (except for medical reasons). In the Bodhisattva Vows of the Brahma Net Sutra, observed by some monastic communities and some lay followers, distribution of intoxicants is likewise discouraged as well as consumption.
In Judaism, in accordance with the biblical stance against drinking, wine drinking was not permitted for priests and monks The biblical command to sanctify the Sabbath day and other holidays has been interpreted as having three ceremonial meals which include drinking of wine, the Kiddush. The Jewish marriage ceremony ends with the bride and groom drinking a shared cup of wine after reciting seven blessings, and according to western "Ashkenazi" traditions, after a fast day. But it has been customary and in many cases even mandated to drink moderately so as to stay sober, and only after the prayers are over.
During the Seder night on Passover (Pesach) there is an obligation to drink 4 ceremonial cups of wine, while reciting the Haggadah. It has been assumed as the source for the wine drinking ritual at the communion in some Christian groups. During Purim there is an obligation to become intoxicated, although, as with many other decrees, in many communities this has been avoided, by allowing sleep during the day to replace it.
In the 1920s due to the new beverages law, a rabbi from the Reform Judaism movement proposed using grape-juice for the ritual instead of wine. Although refuted at first, the practice became widely accepted by orthodox Jews as well.
At the Cave of the Patriarchs in Hebron--the Ibrahimi Mosque as it is called by the Muslims, the Jewish wine drinking rituals during weddings, the Sabbath day and holidays, are a cause for tension with the Muslims who unwillingly share the site under Israeli authority.
In the movie Animals are Beautiful People, an entire section was dedicated to showing many different animals including monkeys, elephants, hogs, giraffes, and ostriches, eating over-ripe Marula tree fruit causing them to sway and lose their footing in a manner similar to human drunkenness.
In elephant warfare, practiced by the Greeks during the Maccabean revolt and by Hannibal during the Punic wars, it has been recorded that the elephants would be given wine before the attack, and only then would they charge forward after being agitated by their driver.
It is a regular practice to give small amounts of beer to race horses in Ireland. Ruminant farm animals have natural fermentation occurring in their stomach, and adding alcoholic beverages in small amounts to their drink will generally do them no harm, and will not cause them to become drunk.