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Alcohol Use


Gerald F. O’Malley

, DO, Grand Strand Regional Medical Center;

Rika O’Malley

, MD, Grand Strand Medical Center

Reviewed/Revised Dec 2022
Topic Resources

Alcohol (ethanol) is a depressant (it slows down brain and nervous system functioning). Consuming large amounts rapidly or regularly can cause health problems, including organ damage, coma, and death.

  • Genetics and personal characteristics may play a part in the development of alcohol-related disorders.

  • Drinking too much alcohol may make people sleepy or aggressive, impair coordination and mental function, and interfere with work, family relations, and other activities.

  • Drinking too much alcohol for a long time can make people dependent on alcohol and damage the liver, brain, and heart.

  • Doctors may use questionnaires or determine the blood alcohol level to help identify people with an alcohol-related disorder.

  • Immediate treatment for overdose may include assistance with breathing, fluids, thiamin and sometimes other vitamins (to correct chronic alcohol-related deficiencies), and, for withdrawal, benzodiazepines.

  • Detoxification and rehabilitation programs can help people with severe alcohol-related disorders.

About half of adults in the United States drink alcohol, 20% are former drinkers, and 30 to 35% are lifetime abstainers. Drinking large amounts of alcohol (more than 2 to 6 drinks per day) for extended periods can damage a number of organs, especially the liver, heart, and brain. However, drinking a moderate amount of alcohol may reduce the risk of death from heart and blood vessel (cardiovascular) disorders. Nonetheless, drinking alcohol for this purpose is not recommended, especially when other safer, more effective preventive measures are available.

Alcohol-related disorders

Overview of Alcohol Use Disorder

Most people do not consume enough alcohol or consume it often enough to impair their health or interfere with their activities. However, approximately 14% of adults in the United States have a problem with alcohol use (alcohol use disorder, also known as alcoholism). Men are 2 to 4 times more likely than women to develop alcohol use disorder. Alcohol and other substance use disorders Substance Use Disorders Substance use disorders generally involve behavior patterns in which people continue to use a substance (for example, a recreational drug) despite having problems caused by its use. The substances... read more involve people continuing to use a substance even though they have problems caused by its use.


Did You Know...

  • Drinking very large amounts of alcohol can quickly cause death.

Alcohol use can lead to many destructive behaviors and effects:

  • Drunk driving

  • Physical injury from falls, fights, or motor vehicle accidents

  • Violence, including domestic violence

Drunkenness may disrupt family and social relationships. The divorce rate is 50% higher when one spouse is a heavy drinker. Extreme absenteeism from work can lead to unemployment.

Special populations

Women may be more sensitive to the effects of alcohol than men, even on a per-weight basis.

Older people may be more sensitive to the effects of alcohol than younger adults.

Although sensitivity to the effects of alcohol may vary with age, people of all ages are susceptible to alcohol use disorders. Increasingly, drug and substance use and abuse among adolescents Substance Use in Adolescents Substance use among adolescents ranges from experimentation to severe substance use disorders. All substance use, even experimental use, puts adolescents at risk of short-term problems, such... read more has been linked with especially disastrous consequences. Those who start drinking at an early age (particularly the preteen years) are much more likely to become dependent on alcohol as adults.

Causes of Alcohol Use Disorder

Alcohol use disorder involves heredity to some extent. Blood relatives of people with alcohol use disorder are more likely to have alcohol use disorder than people in the general population, and alcohol use disorder is more likely to develop in biologic children of people with alcohol use disorder than in adopted children.

Some research suggests that people at risk of alcohol use disorder are less easily intoxicated than people who are not problem drinkers. That is, their brains are less sensitive to the effects of alcohol. Blood relatives of people with alcohol use disorder may have this trait.

Certain factors and personality traits may predispose people to alcohol use disorder. People with alcohol use disorder tend to feel isolated, lonely, shy, depressed, or hostile. They may act self-destructively. Whether such traits are the cause of alcohol use disorder or the result is not certain.

Symptoms of Alcohol Use Disorder

Alcohol causes three basic types of problems:

Immediate effects

Alcohol has almost immediate effects because it is absorbed faster than it is processed (metabolized) and eliminated from the body. As a result, alcohol levels in the blood rise rapidly. Effects can occur within a few minutes of drinking.

Effects vary greatly from person to person. For example, people who drink regularly (2 or more drinks per day) are less affected by a given amount of alcohol than those who normally do not drink or drink only socially, a phenomenon termed tolerance. People who have developed tolerance to alcohol may also be tolerant to other drugs that slow brain function, such as barbiturates and benzodiazepines.

Effects vary depending on the level of alcohol in the bloodstream, which is usually expressed in the United States in terms of milligrams per deciliter (1/10 liter of blood), abbreviated mg/dL and in other parts of the world as millimoles per liter abbreviated mmol/L. Actual blood levels required to produce given symptoms vary greatly with tolerance, but in typical users who have not developed tolerance, the following symptoms are typical:

  • 20 to 50 mg/dL (4.3 to 10.9 mmol/L): Tranquility, mild drowsiness, some decrease in fine motor coordination, and some impairment of driving ability

  • 50 to 100 mg/dL (10.9 to 21.7 mmol/L): Impaired judgment and a further decrease in coordination

  • 100 to 150 mg/dL (21.7 to 32.6 mmol/L): Unsteady gait, slurred speech, loss of behavioral inhibitions, and memory impairment

  • 150 to 300 mg/dL (32.6 to 65.1 mmol/L): Delirium and lethargy (likely)

  • 300 to 400 mg/dL (65.1 to 86.8 mmol/L): Often unconsciousness

  • 400 mg/dL (86.8 mmol/L): Possibly fatal

Vomiting is common with moderate to severe alcohol intoxication. Because people may be very drowsy, vomited material may enter the lungs (be aspirated), sometimes leading to pneumonia Aspiration Pneumonia and Chemical Pneumonitis Aspiration pneumonia is lung infection caused by inhaling mouth secretions, stomach contents, or both. Chemical pneumonitis is lung irritation caused by inhalation of substances irritating or... read more and death.

In the United States, all states define driving with a blood alcohol content (BAC) at or above 80 mg/dL (17.4 mmol/L; 0.08%) as a crime, but specific state laws and penalties vary.


The effects of a particular blood level differ in chronic drinkers. Many seem unaffected and appear to function normally with relatively high levels, such as 300 to 400 mg/dL (65.1 to 86.8 mmol/L).

Alcohol, even in moderate doses, interferes with short-term memory formation which may cause blackouts. The intoxicated individual may seem gregarious and loquacious but will have limited memory of the blackout period.

Long-term effects

Prolonged use of excessive amounts of alcohol damages many organs of the body, particularly the liver (alcohol-related liver disease Alcohol-Related Liver Disease ). Because people may not eat an adequate diet, they may also develop severe vitamin and other nutritional deficiencies.


Alcohol-related liver disease Alcohol-Related Liver Disease Alcohol-related liver disease is liver damage caused by drinking too much alcohol for a long time. In general, the amount of alcohol consumed (how much, how often, and for how long) determines... read more Alcohol-Related Liver Disease includes liver inflammation (hepatitis Overview of Hepatitis Hepatitis is inflammation of the liver. (See also Overview of Acute Viral Hepatitis and Overview of Chronic Hepatitis.) Hepatitis is common throughout the world. Hepatitis can be Acute (short-lived) read more ), fatty liver Fatty Liver Fatty liver is an abnormal accumulation of certain fats (triglycerides) inside liver cells. People with fatty liver may feel tired or have mild abdominal discomfort but otherwise have no symptoms... read more , and liver scarring (cirrhosis Cirrhosis of the Liver Cirrhosis is the widespread distortion of the liver's internal structure that occurs when a large amount of normal liver tissue is permanently replaced with nonfunctioning scar tissue. The scar... read more Cirrhosis of the Liver ). An alcohol-damaged liver is less able to rid the body of toxic waste products, which can cause brain dysfunction (hepatic encephalopathy Hepatic Encephalopathy Hepatic encephalopathy is deterioration of brain function that occurs in people with severe liver disease because toxic substances normally removed by the liver build up in the blood and reach... read more ). People developing hepatic encephalopathy become dull, sleepy, stuporous, and confused and may lapse into a coma. Hepatic coma is life threatening and needs to be treated immediately.

Usually, people with liver failure also have liver flap (asterixis Hepatic Encephalopathy Hepatic encephalopathy is deterioration of brain function that occurs in people with severe liver disease because toxic substances normally removed by the liver build up in the blood and reach... read more ). When the arms and hands are outstretched, the hands suddenly drop, then resume their original position. Liver flap resembles but is not a tremor.

Cirrhosis of the liver Cirrhosis of the Liver Cirrhosis is the widespread distortion of the liver's internal structure that occurs when a large amount of normal liver tissue is permanently replaced with nonfunctioning scar tissue. The scar... read more Cirrhosis of the Liver causes pressure to build up in the blood vessels around the liver (portal hypertension Portal Hypertension Portal hypertension is abnormally high blood pressure in the portal vein (the large vein that brings blood from the intestine to the liver) and its branches. Cirrhosis (scarring that distorts... read more ). Built up pressure in these blood vessels can cause swelling of blood vessels in the stomach and esophagus (varices). These swollen vessels can rupture and bleed heavily, causing people to vomit blood. This bleeding is a particular problem because the damaged liver does not produce enough of the substances that make blood clot.

Damage to the nerves and parts of the brain also can be caused by excessive alcohol use. When the nerves to the arms and legs (peripheral nerves Overview of the Peripheral Nervous System The peripheral nervous system refers to the parts of the nervous system that are outside the central nervous system, that is, those outside the brain and spinal cord. Thus, the peripheral nervous... read more ) are affected, people may have loss of sensation or feel pins and needles in their hands and feet. People may develop a chronic tremor Tremor A tremor is an involuntary, rhythmic, shaking movement of part of the body, such as the hands, head, vocal cords, trunk, or legs. Tremors occur when muscles repeatedly contract and relax. (See... read more . Damage to the part of the brain that coordinates movement (cerebellum) can lead to poorly controlled movement of the arms and legs and affect balance. Heavy long-term alcohol use can result in irreversible brain damage and psychosis. It can also damage the lining (myelin sheath) of nerves in the brain, resulting in a rare disorder called Marchiafava-Bignami disease. People with this disorder become agitated, confused, and demented. Some develop seizures and go into a coma before dying.

Existing depression Depression Depression is a feeling of sadness and/or a decreased interest or pleasure in activities that becomes a disorder when it is intense enough to interfere with functioning. It may follow a recent... read more may be worsened by drinking alcohol, and people with alcohol use disorder are more likely to become depressed than people who are not problem drinkers. Because alcohol-related disorders, especially binge drinking, often causes deep feelings of remorse during dry periods, people with alcohol use disorder are prone to suicide even when they are not drinking.

Severe problems in the developing fetus, including low birth weight, short body length, small head size, heart damage, muscle damage, and low intelligence or intellectual disability, can be caused by alcohol use in pregnant women. These effects are called the fetal alcohol syndrome Alcohol Certain substances, including caffeine, aspartame, alcohol, and tobacco, may have harmful effects on pregnant women and fetuses. Illicit drugs include amphetamines, bath salts, cocaine, hallucinogens... read more . Avoidance of alcohol is therefore recommended during pregnancy.

Withdrawal symptoms

If people who drink continually for a period of time suddenly stop drinking, withdrawal symptoms are likely. For example, withdrawal can occur during hospitalization (for example, for elective surgery) because drinkers are unable to obtain alcohol.

Withdrawal symptoms vary from mild to severe. Severe untreated alcohol withdrawal can be fatal.

Mild to moderate withdrawal usually begins within 6 hours after drinking stops. Mild symptoms include tremor, headache, weakness, sweating, and nausea. Some people have seizures Seizure Disorders In seizure disorders, the brain's electrical activity is periodically disturbed, resulting in some degree of temporary brain dysfunction. Many people have unusual sensations just before a seizure... read more (called alcohol-related epilepsy or rum fits).

Alcohol-related hallucinosis may occur in heavy drinkers who stop drinking. They hear voices that seem accusatory and threatening, causing apprehension and terror. Alcohol-related hallucinosis may last for days and can be controlled with antipsychotic medications, such as chlorpromazine or thioridazine.

Delirium tremens (DTs) is the most serious group of withdrawal symptoms. Usually, delirium tremens does not begin immediately. Rather, it appears about 48 to 72 hours after the drinking stops. People are initially anxious. Later, they become increasingly confused, do not sleep well, have frightening nightmares, sweat excessively, and become very depressed. The pulse rate speeds up and the blood pressure rises. Fever typically develops. The episode may escalate to include fleeting hallucinations, illusions that arouse fear and restlessness, and disorientation with visual hallucinations that may be terrifying. Objects seen in dim light may be particularly terrifying, and the people become extremely confused. Their balance is impaired, sometimes making them think the floor is moving, the walls are falling, or the room is rotating. As the delirium progresses, a persistent tremor develops in the hands and sometimes extends to the head and body. Most people become severely uncoordinated. Delirium tremens can be fatal, particularly when untreated.

Screening for Alcohol Use Disorder

Some people may not know that their amount of drinking could be a problem. Others know but do not want to admit that they have an alcohol problem. Therefore, health care practitioners do not wait for people to ask for help. They may suspect alcohol use disorder in people whose behavior changes inexplicably or whose behavior becomes self-destructive. They may also suspect alcohol use disorder when medical problems, such as high blood pressure High Blood Pressure High blood pressure (hypertension) is persistently high pressure in the arteries. Often no cause for high blood pressure can be identified, but sometimes it occurs as a result of an underlying... read more High Blood Pressure or stomach inflammation (gastritis Gastritis Gastritis is inflammation of the stomach lining. The inflammation can be caused by many factors, including infection, stress resulting from severe illness, injury, use of aspirin and other nonsteroidal... read more Gastritis ), do not respond to usual treatment.

Many practitioners periodically screen people for alcohol-related problems by asking about their use of alcohol. Questions may include the following:

  • On average, how many days per week do you drink alcohol?

  • On a typical day when you drink, how many drinks do you have?

  • What is the maximum number of drinks you had on any given occasion in the past month?

If doctors suspect alcohol use disorder, they may ask more specific questions about consequences of drinking, such as the following:

  • Have you ever felt you should cut down on your drinking?

  • Does criticism of your drinking annoy you?

  • Have you ever felt guilty about drinking?

  • Have you ever had an “eye opener” (a drink first thing in the morning) to steady your nerves or to get rid of a hangover?

Two or more “yes” answers to these questions indicate a probable alcohol use disorder.

Diagnosis of Alcohol Use Disorder

  • Self-reports of alcohol intoxication

  • Blood tests

  • Screening questionnaires

Tests may include blood tests to determine the amount of alcohol in the blood and the blood sugar level, urine tests for certain toxic substances, and computed tomography Computed Tomography and Magnetic Resonance Imaging of the Digestive Tract Computed tomography (CT) and magnetic resonance imaging (MRI) scans are good tests for assessing the size and location of abdominal organs. Additionally, cancerous (malignant) or noncancerous... read more (CT) of the head. Doctors do not assume that simply because people have alcohol on their breath that nothing else could be wrong.

For legal purposes (for example, when people are in vehicle crashes or are acting abnormally at work), alcohol levels can be measured in the blood or estimated by measuring the amount in a sample of exhaled breath.

In people with long-term alcohol use, blood tests may be done to check for abnormalities in liver function and evidence of other organ damage. If symptoms are very severe, an imaging test such as CT may be done to rule out a brain injury or infection.

Treatment of Alcohol Use Disorder

Treatment may involve the following situations:

  • People are brought in because they have symptoms related to high blood alcohol levels.

  • People come because they have intolerable withdrawal symptoms. However, people who develop alcohol withdrawal symptoms usually treat themselves by drinking.

  • People come because they do not want to continue drinking.

Emergency treatment

Emergency treatment is needed when very large amounts of alcohol consumed or alcohol withdrawal causes moderate to severe symptoms.

There is no specific antidote for acute intoxication:

Did You Know...

  • There is no specific antidote for acute alcohol intoxication: coffee, fluids, vitamins, or other remedies do not help people become sober.

For alcohol withdrawal symptoms, doctors often prescribe a benzodiazepine (a mild sedative) for a few days. It reduces agitation and helps prevent some withdrawal symptoms, seizures, and delirium tremens. Because people can become dependent on benzodiazepines, these medications are used for only a short time. Antipsychotic medications Antipsychotic Drugs Psychosis refers to symptoms such as delusions, hallucinations, disorganized thinking and speech, and bizarre and inappropriate motor behavior that indicate loss of contact with reality. A number... read more are sometimes given to people with alcohol-related hallucinosis.

Delirium tremens can be life threatening and is treated aggressively to control the high fever and severe agitation. People are treated in an intensive care unit if possible. Treatment usually includes the following:

With such treatment, delirium tremens usually begins to clear within 12 to 24 hours of its beginning, but severe cases may last for 5 to 7 days. Most people do not remember events during severe withdrawal after it resolves.

After any urgent medical problems are resolved, further treatment depends on the severity of alcohol use and the person's other medical and mental health disorders. If people have not become dependent on alcohol, doctors may discuss the serious consequences of alcohol use with them, recommend ways to reduce or stop their drinking, and schedule follow-up visits to check on how well they are doing.

For people with more severe alcohol use, particularly those who have coexisting medical and mental health disorders, a detoxification and rehabilitation program may be recommended.

Detoxification and rehabilitation

In the first phase of detoxification and rehabilitation, alcohol is completely withdrawn, and any withdrawal symptoms are treated. Then people with alcohol use disorder have to learn ways to modify their behavior. Without help, most problem drinkers relapse within a few days or weeks. Rehabilitation programs, which combine psychotherapy with medical supervision, can help. People are warned about how difficult stopping is. They are also taught ways to enhance the motivation to stop and to avoid situations that are likely to trigger drinking. Treatment is tailored to the individual. These programs also enlist the support of family members and friends. Self-help groups, such as Alcoholics Anonymous , can also help.

Sometimes certain medications (disulfiram, naltrexone, acamprosate, and clonidine) can help people with alcohol use disorder avoid drinking alcohol. However, medications can typically help only if people are motivated and cooperative and if the medications are used as part of an ongoing intensive counseling regimen. Results vary.

Disulfiram deters drinking because it interferes with alcohol metabolism, causing acetaldehyde (a substance that results from the breakdown of alcohol) to build up in the bloodstream. Acetaldehyde makes people feel ill. Within 5 to 15 minutes after people who took disulfiram drink alcohol, the buildup of acetaldehyde causes

  • Facial flushing

  • A throbbing headache

  • A rapid heart rate

  • Rapid breathing

  • Sweating

Nausea and vomiting may follow 30 to 60 minutes later. These uncomfortable and potentially dangerous reactions last 1 to 3 hours.

The discomfort from drinking alcohol after taking disulfiram is so intense that few people risk drinking alcohol—even the small amount in some over-the-counter cough and cold preparations or some foods.

Disulfiram must be taken every day in order for it to be effective in stopping drinking.

The following people should not use disulfiram:

Naltrexone alters the effects of alcohol on certain chemicals made by the brain (endorphins), which may be associated with alcohol craving and consumption. This medication is effective in most people who take it consistently. A long-acting form can be given by injection once a month. Naltrexone, unlike disulfiram, does not make people sick. Thus, people taking naltrexone can continue to drink. Naltrexone should not be taken by people who have hepatitis Overview of Hepatitis Hepatitis is inflammation of the liver. (See also Overview of Acute Viral Hepatitis and Overview of Chronic Hepatitis.) Hepatitis is common throughout the world. Hepatitis can be Acute (short-lived) read more or certain other liver disorders.

Clonidine is a drug that affects certain parts of the brain and is typically used for high blood pressure but can help relieve some of the effects of alcohol withdrawal.

Alcoholics Anonymous: A Path to Recovery

No approach has benefited so many people with alcohol use disorder as effectively as Alcoholics Anonymous (AA). AA is an international fellowship of people who want to stop drinking. There are no dues or fees. The program operates on the basis of the “Twelve Steps,” which offers problem drinkers a new way of living without alcohol. Members of the fellowship typically work with a sponsor—a fellow member who is abstaining from alcohol use—who offers guidance and support.

AA operates within a spiritual context but is not affiliated with any specific ideology or religious doctrine. However, alternative organizations, such as LifeRing Recovery (Secular Organizations for Sobriety), exist for those seeking a more secular approach.

AA helps its members in other ways as well. It provides a place where people recovering can socialize away from alcohol and with friends who do not drink and who are always available for support when the urge to start drinking again becomes strong. In meetings, people with alcohol use disorder hear other people relate—to the entire group—how they are struggling every day to avoid taking a drink. By providing a means to help others, AA builds self-esteem and confidence formerly found only in drinking alcohol. Most metropolitan areas have many AA meetings available day and night, 7 days a week. People with alcohol use disorder are encouraged to try several different meetings and to attend those at which they feel most comfortable.

More Information

The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

  • Al-Anon Family Groups: Support services for adults who abuse alcohol, adults who grew up with an alcohol use disorder, and teens affected by someone else's problematic use of alcohol.

  • Alcoholics Anonymous: International fellowship of people with a drinking problem that pioneered the 12-step approach to help its members overcome their addiction to alcohol and help others to do the same.

  • LifeRing: Support for people with drug and alcohol use problems by facilitating sharing of practical experiences and sobriety support as an alternative to traditional 12-step programs.

  • National Institute on Alcohol Abuse and Alcoholism (NIAAA): Supports and conducts research on how alcohol use impacts human health and well-being.

Drugs Mentioned In This Article

Generic Name Select Brand Names
ARYMO ER, Astramorph PF, Avinza, DepoDur, Duramorph PF, Infumorph, Kadian, MITIGO, MORPHABOND, MS Contin, MSIR, Opium Tincture, Oramorph SR, RMS, Roxanol, Roxanol-T
No brand name available
Depade, ReVia, Vivitrol
Mellaril, Mellaril Concentrate , Mellaril-S
Catapres, Catapres-TTS, Duraclon, Kapvay, NEXICLON XR
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