Alcohol Intoxication

Medical Editor:

Alcohol Intoxication Facts

  • A person is said to suffer from alcohol intoxication when the quantity of alcohol the person consumes produces behavioral or physical abnormalities.
  • In other words, the person's mental and physical abilities are impaired.
  • In addition to the signs of physical and mental impairment, alcohol levels can also be measured in the blood.
  • Most states have specific levels at which the driving of a motor vehicle is forbidden.

Alcohol Intoxication Causes

Alcohol is a generic term for ethanol, which is a particular type of alcohol produced by the fermentation of many foodstuffs - most commonly barley, hops, and grapes. Other types of alcohol commonly available such as methanol (common in glass cleaners), isopropyl alcohol (rubbing alcohol), and ethylene glycol (automobile antifreeze solution) are highly poisonous when swallowed, even in small quantities.

Ethanol produces intoxication because of its depressive effects on various areas of the brain causing the following physical and mental impairments in a progressive order as the persons alcohol level increases (the person becomes more and more intoxicated).

  • Disinhibition of normal social functioning
  • Euphoria (excessive talking, showing off)
  • Ataxia (uncoordinated gait-walking)
  • Poor judgment
  • Loss of memory
  • Slurred speech
  • Worsening ataxia
  • Vomiting
  • Confusion and disorientation
  • Progressive lethargy and coma
  • Ultimately the shutdown of the respiratory centers and death

What happens to brain function: Alcohol increases the effect of the body's naturally occurring neurotransmitter GABA (gamma amino butyric acid). Neurotransmitters are substances that chemically connect the signals from one nerve to the next allowing a signal to flow along a neural pathway. An inhibitory neurotransmitter (alcohol) reduces this signal flow in the brain. This explains how alcohol depresses both a person's mental and physical activities. By way of comparison, cocaine does the opposite by producing a general excitatory effect on the nervous system.

Available forms and measurement: A standard "drink" of ethanol consists of 10 grams. This amount is equal to:

  • Ten ounces (300 cc) of regular beer (5% alcohol content);
  • Three-and-a-quarter ounces of wine (12% alcohol content); or
  • One ounce of hard liquor (40% alcohol content, 80 "proof").

Absorption: Approximately 20% of ethanol is absorbed into the bloodstream directly from the stomach, and 80% from the small intestine. Consequently, the longer the ethanol/alcohol remains in the stomach, the slower it will be absorbed and the lower the peak in the blood alcohol concentration (BAC).

  • This explains the apparent sobering effect of food, which slows the process of emptying the stomach contents, slows the absorption of alcohol, and thus reduces the peak blood alcohol concentration reached.
  • When alcohol is consumed with food, absorption generally is complete in 1-3 hours during which time the blood alcohol concentration will peak. If no further alcohol is consumed, sobering up will follow this peak level of blood alcohol concentration.

Distribution: Ethanol is highly soluble in water and is absorbed much less in fat. So alcohol tends to distribute itself mostly in tissues rich in water (muscle) instead of those rich in fat.

  • Two people may weigh the same, yet their bodies may have different proportions of tissue containing water and fat. Think of a tall, thin person and a short, obese person who both weigh 150 pounds. The short, obese person will have more fat and less water making up his/her body than the tall, thin person. If both people, in this example, consume the same amount of alcohol, the short, obese person will end up with a higher blood alcohol concentration. This is because the alcohol he drank was spread into a smaller water "space."
  • Women's bodies, on average, have more fat and less water than men's bodies. Using the same logic, this means that a woman will reach a higher blood alcohol concentration than a man of the same weight when both drink the same amount of alcohol.

Metabolism (elimination): Metabolism is the method by which the body processes alcohol and everything else a person eats or drinks. Some of the alcohol is converted to other substances (such as fat, as in "beer belly"). Some is burned as energy and converted to water and carbon dioxide. A small amount is excreted unchanged in the breath and urine. The liver metabolizes about 90% of the ethanol. The lungs excrete about 5% during exhalation (breathing out). Alcohol excretion by the lungs forms the basis for Breathalyzer testing. Another 5% is excreted into the urine.

  • The average person metabolizes about one standard drink (10 grams) per hour.
  • Heavy drinkers have more active livers ,and may be able to metabolize up to three drinks per hour.
  • People with liver diseases will metabolize less than one drink per hour. In many chronic alcoholics, the liver becomes ineffective and can no longer metabolize alcohol, or anything else, efficiently. This is known as alcoholic cirrhosis.
  • In alcoholic cirrhosis, the liver cells become badly scarred. This scarring has the effect of blocking blood flow through the liver, impeding exchange of metabolic chemicals into and out of the liver cells, and damaging the cells' ability to function.
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Alcohol Intoxication Signs and Symptoms

The effects of alcohol vary widely from person to person. Several factors can account for obvious differences in how certain amounts of alcohol can affect one person more than another. These factors also affect the particular signs and symptoms the person may exhibit to indicate alcohol intoxication.

Major factors accounting for this variation in signs and symptoms:

  • Prior experience with alcohol: A longtime, heavy drinker may achieve blood alcohol concentration levels that would kill the average casual drinker. Conversely, a novice drinker may have severe symptoms with the ingestion of a moderate amount of alcohol. As a person's drinking increases, his/her liver will increase its capacity to metabolize alcohol. In addition, the brain of a heavy drinker becomes used to frequent, even constant, high blood alcohol concentrations. This habituation in a heavy drinker can backfire if this person suddenly stops drinking. The person may go into alcohol withdrawal and develop seizures or a condition called delirium tremens (DTs).
  • Taking medications: The effects of alcohol are enhanced if a person is taking other prescription medications, especially those of the sedative class such as sleeping pills or anti-anxiety medications. A person who is not habituated to either alcohol or sedatives may experience serious harm, or even death, if taking prescribed doses. Together, they can be a deadly combination. A person may be taking medications prescribed by a doctor or over-the-counter medications, and may not know about these unintended consequences.
  • Medical conditions: The presence of a wide variety of medical conditions may affect how a person reacts to alcohol.
  • Smell of alcohol on the breath: There is a very poor correlation between the strength of the smell of alcohol on the breath and the blood alcohol concentration. Pure alcohol has very little smell. It is the metabolism of other substances in alcoholic beverages that produces most of the smell. This explains why a person who drinks large amounts of high-proof vodka (a more pure form of alcohol) may have only a faint smell of alcohol on the breath. On the other hand, a person who drinks a modest amount of beer may have a strong smell of alcohol on the breath.
  • Scale of effects: In the average social drinker (defined as someone who drinks no more than two standard drinks per day), there is a rough correlation between blood alcohol concentration and how the person acts.
  • Blood alcohol concentration. Blood alcohol concentration commonly is expressed in milligrams per deciliter (mg/dL). Using this measure, 100 mg/dL roughly is equal to one part alcohol in 1000 parts of water (or blood). Consequently, 100 mg/dL would be equal to a 0.1% concentration. In most states, 100 mg/dL represents the threshold concentration above which a person is legally intoxicated when operating a motor vehicle.
    • To find out more about blood alcohol concentration and how it affects a person, go to the Blood Alcohol Educator Web site of the Century Council and the University of Illinois.
    • TThe following scale details the expected effects of alcohol at various blood alcohol concentrations. There is a tremendous variation from person to person, and not all people exhibit all the effects. This scale would apply to a typical social drinker:
      • 50 mg/dL: Loss of emotional restraint, vivaciousness, feeling of warmth, flushing of skin, mild impairment of judgment
      • 100 mg/dL: Slight slurring of speech, loss of control of fine motor movements (such as writing), confusion when faced with tasks requiring thinking, emotionally unstable, inappropriate laughter
      • 200 mg/dL: Very slurred speech, staggering gait, double vision, lethargic but able to be aroused by voice, difficulty sitting upright in a chair, memory loss
      • 300 mg/dL: Stuporous, able to be aroused only briefly by strong physical stimulus (such as a face slap or deep pinch), deep snoring
      • 400 mg/dL: Comatose, not able to be aroused, incontinent (wets self), low blood pressure, irregular breathing
      • 500 mg/dL: Death possible, either from cessation of breathing, excessively low blood pressure, or vomit entering the lungs without the presence of the protective reflex to cough it out
  • Other conditions that look like alcohol intoxication: It is important to recognize the symptoms of alcohol intoxication not only to confirm the presence and severity of the alcohol effect, but also to be able to differentiate the symptoms from other conditions that may coexist, mimic, or mask the symptoms of alcohol intoxication.

Home Care for Alcohol Intoxication

The majority of people with simple alcohol intoxication can be cared for by a friend or relative at home.

  • Remove the person from all sources of alcohol. Remove the person from the bar or party. If in a home environment, get rid of all the alcohol.
  • Provide a safe environment (prevent falls, keep away from dangerous machines and objects, keep from driving vehicles).
  • Find out if only ethanol has been ingested. Determine if the person has taken any medications, illegal drugs, or nonethanol alcohols.
  • See if the person is easy to arouse when spoken to or with a slight shake of a shoulder.
  • Make sure that the person's condition is not due to an underlying medical cause or injury. Ask about other conditions and look for any evidence of a head injury or other trauma.
  • Have someone in constant attendance to ensure that the person is improving, and to obtain medical assistance as needed. If the person does not feel comfortable monitoring the condition of the intoxicated person, then it would be best to take the person to the hospital.
  • No medications will speed up the sobering process. Caffeine (by drinking coffee) and cold showers have a minimal and very temporary effect.

NOTE: It is extremely common for an intoxicated person to vomit. However, vomiting more than once may be a sign of head injury or other cause of serious illness. If an intoxicated person vomits more than once and is not completely coherent, then he/she should be taken to the nearest hospital's emergency department for evaluation.

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When to Seek Medical Care for Alcohol intoxication

If all home care conditions cannot be assured, or if a caretaker feels uncomfortable monitoring the intoxicated person, or if there is any doubt about the person's condition, then take the person to the nearest hospital's emergency department. In addition, the person may need medical attention to address chronic medical conditions unrelated to the alcohol intoxication. These could be conditions such as diabetes, renal (kidney) failure, or epilepsy (seizures).

Alcohol Intoxication Diagnosis

The doctor will assess the person suspected of alcohol intoxication to answer the following medical questions and provide the appropriate care. Friends or family who accompany an intoxicated person (or person suspected to be intoxicated) to the hospital can provide invaluable information regarding recent events as well as past medical history.

Does the blood alcohol concentration correspond to the physical exam and the person's apparent degree of intoxication?

  • Most importantly, in a lethargic, intoxicated person, a doctor may be more interested in how low the blood alcohol concentration is rather than how high it is. This is because the lower the blood alcohol concentration, the less likely that alcohol explains the abnormal drowsiness.
  • The dilemma: If the blood alcohol concentration is found to be inappropriately low for the apparent degree of intoxication (for example, a blood alcohol concentration of 150 mg/dL in a person who is deeply lethargic), then the doctor must look elsewhere for an explanation. Conversely, a blood alcohol concentration of 300 mg/dL may perfectly explain a stuporous state while masking a coexisting, serious, life-threatening condition.

Is there any evidence of serious physical injury?

  • In people with mild-to-moderate intoxication, the physical exam alone may often be sufficient to exclude serious physical injuries or at least permit a later reassessment.
  • The existence or extent of a head injury may be difficult or impossible to assess in a lethargic, intoxicated person. Important information about the person's medical history and recent activities is often lacking, and a person is usually in no condition to talk coherently.

Are any medical conditions contributing to the person's condition?

  • The assessment of medical conditions in an intoxicated person can be quite complex, as the two often coexist. The doctor will need to assess the status of the person's chronic medical illnesses plus the effects of any acute illnesses and injuries. Diagnosis and further investigation of these possibilities are guided by available medical history, physical exam, and results of standard blood tests.
  • The doctor will check (to rule out) common conditions that may mimic those of alcohol intoxication, such as head injuries , hypoglycemia (low blood sugar), seizure disorders, and the influence of illicit drugs (marijuana, cocaine, amphetamines, and opiates). Common opiates are heroin and codeine. In addition, psychiatric conditions, especially depression and alcohol abuse, frequently coexist. Until the alcohol wears off, it can be exceedingly difficult for the physician to separate the effects of each, and make sure the individual was not attempting suicide.
  • The doctor will look for other specific conditions. For example, if there is fever, the physician might consider meningitis, pneumonia, or some other serious infection that might be causing a change of mental status. If the blood pressure is extremely low, the physician may consider internal bleeding.
  • The doctor will be looking for evidence of chronic alcohol abuse, such as red spots on the skin (called spider angiomas), an enlarged liver, or yellow eyes or skin (jaundice, caused by damage to the liver).

Alcohol Intoxication, Physician Treatment and Follow-up

Treatment: No specific treatment can reverse the effects of alcohol intoxication.

  • Intoxicated people often receive IV fluids for dehydration (alcohol is a diuretic and increases urine output) and B complex vitamins for dehydration and to prevent delirium, and as a precaution or treatment for vitamin deficiency.
  • In severe cases - those of severe stupor and coma - the person should be intubated (a breathing tube placed in the patient's airway) to support respirations (which may stop spontaneously) and to protect the lungs from filling with vomit/secretions.
    • Intubation involves placing a short, flexible plastic tube into the windpipe (trachea) just below the vocal cords and connecting the tube to a respirator machine. The tip of the tube has a small donut-shaped balloon around it, which is inflated to seal the end of the tube to the inside of the windpipe. This accomplishes two things:
      • It prevents the air from the respirator from leaking out into the mouth instead of going into the lungs.
      • It provides a protective seal so that a large amount of vomit in the mouth is prevented from entering the lungs where it could cause damage and possible suffocation.

Follow-up: Barring any major complications, most intoxicated people may go home from the hospital's emergency department. For some medical and many legal reasons, most hospitals prefer to keep people suspected of alcohol intoxication under observation until their blood alcohol concentration falls to below 80 mg/dL.

  • In most people, the liver metabolizes about 10 grams of ethanol per hour. This corresponds to a blood alcohol concentration fall of about 20 mg/dL per hour. Thus, the length of time a person (and family) will need to wait until discharge may be expressed by the formula (blood alcohol concentration-100)/20 = the wait in hours. For example, the blood alcohol concentration from a blood sample drawn at midnight is 280 mg/dL. (280-100)/20 = 9. The blood alcohol concentration should fall to 100 mg/dL by 9 am (midnight plus 9 hours).
  • A social worker may talk with the intoxicated person prior to discharge from the hospital. The social worker may advise the person to go to an alcohol treatment center. This is an extremely difficult situation because many people either don't recognize their problem if they are chronic drinkers, or don't have any desire to correct the situation.
Prescription Drug Abuse: Statistics, Facts, and Symptoms

Driving While Intoxicated: The Facts

FACT: In 2014, 9,967 people were killed in vehicle crashes involving alcohol in the United States.

FACT: Numerous studies demonstrate that almost all drivers are impaired at a level of 80 mg/dL with respect to critical driving skills such as braking, steering, and changing lanes. Impairment begins as low as 20 mg/dL and is common at 50 mg/dL. Most significant is that impairment of skills begins at a much lower level than required to exhibit obvious signs of being intoxicated. The "per se" level mandated by the federal government for drivers of commercial vehicles is a mere 40 mg/dL (0.04%). This applies to all 50 states.

In 1992, the National Highway Transportation and Safety Administration recommended that all states lower their illegal per se blood alcohol concentration levels to 80 mg/dL (0.08%). Currently, all 50 states and the District of Columbia have per se laws making it illegal to drive with a blood alcohol concentration of 80 mg/dL or greater.

The vast majority of European countries have established lower blood alcohol concentration cutoffs than the United States.


Liver damage with alcoholic cirrhosis. Image from the National Institute on Alcohol Abuse and Alcoholism (NIAAA).
Liver damage with alcoholic cirrhosis. Image from the National Institute on Alcohol Abuse and Alcoholism (NIAAA). Click to view larger image.

Total adult (15+) per capita consumption, in litres of pure alcohol, 2005(a)

a Best estimates of 2005 using average recorded alcohol consumption 2003-2005 (minus tourist consumption) and unrecorded alcohol consumption 2005.


Alcohol Quiz IQ
Reviewed on 11/20/2017

Medically reviewed by John A. Daller, MD; American Board of Surgery with subspecialty certification in surgical critical care


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National Highway Traffic Safety Administration (NHTSA).

National Institute on Alcohol Abuse and Alcoholism.

Rosen P, Barkin RM, Danzl DF. Alcohol related diseases. In: Emergency Medicine: Concepts and Clinical Practice. 4th ed. Mosby-Year Book;1998. Global status report on alcohol and health.

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