Alcohol has a relatively short half-life in comparison to other substances. Once you consume alcohol and it enters your bloodstream, it is metabolized at a rate of 20 milligrams per deciliter per hour, which works out to roughly one drink per hour. Alcohol is metabolized at this constant rate in everyone, though alcohol may remain in some people’s systems longer than others.
Your blood-alcohol concentration determines how long it will take for all of the alcohol to be metabolized.
Blood alcohol concentration (BAC) is the amount of alcohol in a person’s bloodstream.
While the intoxicating effects of alcohol will be experienced only for a relatively short period, traces of the substance will linger for much longer. Additionally, traces of alcohol will remain in your blood, urine, hair, and on your breath for various amounts of time. This can be relevant for people who must undergo various forms of drug testing and are concerned about their results, as well as for people who are concerned about their physical or mental performance abilities.
Various tests can be used to detect recent alcohol use. They include:
For about 24 hours after your last alcoholic drink, a breathalyzer can measure your BAC. This is the shortest alcohol testing time frame.
A traditional urine sample can be collected and tested for alcohol use for 12 hours to 48 hours after drinking. Ethyl glucuronide (EGT) urine testing can detect alcohol in your urine for three to five days after your last use.
Traces of alcohol can be detected in hair follicles for up to 90 days after drinking.
A blood test can be used to test for alcohol consumption for up to 12 hours after your last drink.
Saliva tests can be used to detect alcohol for one to five days after drinking.
In addition to being prepared for a drug test, it is important to know how long traces of alcohol stay in your system if you are taking any medications or are going to be starting any. Alcohol can have dangerous interactions with many medications, so it is important to consult your doctor before mixing alcohol with any medicines.
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If you drink five beers in a short time, your BAC will be much higher than if you only drink one beer over dinner. Several factors influence BAC including:
The physical and mental effects of alcohol are felt increasingly as your BAC rises. At a BAC of 0.01 percent to 0.03 percent, it is illegal for anyone under age 21 to drive or ride a bike. At a BAC of 0.04 percent to 0.06 percent, you are likely to feel a sense of relaxation and a minor impairment of judgment and memory. A BAC of 0.08 percent and above constitutes being legally impaired to drive, and you could be arrested on a charge of driving under the influence. At a BAC of 0.1 percent, you begin to experience significant impairment of motor coordination and cognitive judgment.
A BAC of 0.13 percent to 0.15 percent causes substantial gross motor impairment, and the individual may begin to appear sloppy. Severe intoxication marked by mental confusion and the inability to walk without assistance sets in at a BAC of about 0.25 percent. You are likely to lose consciousness at a BAC of 0.35 percent. At a BAC of 0.4 percent and above, coma and death caused by respiratory failure are likely.
If you are drinking, it is important to remain aware of your BAC. Even if you don’t know the exact percentage, you can be aware of the associated symptoms with the different BAC levels. Being alert to how much alcohol is in each drink you consume, as well as how your body typically responds to alcohol, can help keep you mentally and physically safe.
No matter how quickly you consume alcohol or what your personal weight, sex, and medical factors are, alcohol is metabolized at about 0.016 BAC, or 20 milligrams per deciliter, per hour. There is nothing you can do, such as drinking a lot of water, that will speed up this process. Only time will gradually reduce your BAC.
For a person with a BAC of 0.16 percent, it will take about one hour for all alcohol to be eliminated. For a person with a BAC of .08 percent, the legal driving limit, it will take about five hours for all alcohol to be eliminated. A severely intoxicated person with a BAC of about 0.24 percent will take about 15 hours to detox.
Once the acute phase of detox has passed, and you no longer feel the intoxicating effects of alcohol, your body must still work to metabolize the remaining alcohol from your system. American Family Physician recognizes three primary phases of the alcohol withdrawal timeline that vary in severity.
This is known as the mild phase, marked by anxiety, insomnia, nausea, and gastrointestinal upset. It usually starts around eight hours after your last drink.
The moderate phase of detox is identified by high blood pressure, irregular heartbeat, confusion, and mild hyperthermia. This phase typically occurs within one to three days of last use.
The severe stage of detox may involve symptoms of disorientation, impaired attention, hallucinations, and seizures. This phase typically presents itself within one week of taking the last alcoholic drink.
Your experience of the above phases is greatly impacted by the history and extent of your alcohol use. Someone with a short history of mild alcohol use is not likely to experience the most severe stage of detox, though they may still have a headache or nausea, as is often experienced with a hangover. Your detox timeline is likely to be longer and more challenging if you have a more significant history of alcohol misuse. In this case, there are important risks associated with alcohol withdrawal that you should be aware of.
If you have a history of alcohol misuse — you have been using it regularly and consistently for an extended period — you may have developed a physical dependence on it. Once you develop a physical dependence on a drug, you will experience withdrawal symptoms when you greatly reduce or quit using the substance.
In the case of alcohol withdrawal, you must be very cautious about the withdrawal process, as some symptoms can be life-threatening. Typically, withdrawal symptoms begin to show up about eight hours after your last drink, though they may not present themselves until a couple of days later.
The most severe symptoms usually peak around 24 hours to 72 hours after your last drink. Symptoms should subside after that, but they may be felt for some weeks, especially if left untreated.
The most common symptoms of alcohol withdrawal include:
The above symptoms may be mild, or they may cause severe discomfort, but they are not likely to be life-threatening. Some symptoms of alcohol withdrawal, however, are very serious and require medical attention.
Fever, hallucinations, severe confusion, and seizures are all cause for concern and can be fatal if left untreated.
Additionally, it is dangerous to quit alcohol cold turkey, as it can be too great of a shock to your system and cause severe and possibly fatal withdrawal symptoms.
While many of the symptoms of alcohol withdrawal are unavoidable, there are many treatment options available to see you safely through the detox process.
Medically assisted detox is an option offered by many rehab programs. It provides medication management and monitoring of withdrawal symptoms to reduce their severity and prevent any further complications.
The intoxicating effects of alcohol caused by any single episode of drinking will only be felt for several hours, depending on how much you drink. Traces of alcohol, however, can be detected in your urine, hair, blood, and breath for much longer. Whether you want to know the chances of alcohol showing up on a drug test, or you want to determine if it’s safe to take certain medications, understanding how long alcohol stays in your system can help you make informed and safe decisions about your alcohol use.
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(November 2013). Outpatient Management of Alcohol Withdrawal Syndrome. American Family Physician. Retrieved December 2018 from https://www.aafp.org/afp/2013/1101/p589.html
What is BAC? Stanford: Office of Alcohol Policy and Education. Retrieved December 2018 from https://alcohol.stanford.edu/alcohol-drug-info/buzz-buzz/what-bac