The amount of time drugs or alcohol remain in the body depends on many factors, such as the specific substance, the amount taken, and the user’s physical makeup.
Different individuals process substances at different rates. Factors that affect that processing rate include:
- Age: Older individuals may have decreased liver and kidney function, which may cause drugs and/or alcohol to stay in their bodies for longer periods of time.
- Gender: Since men and women’s liver enzymes are different, the rate at which their bodies process drugs and/or alcohol also varies.
- Size and percentage of body fat: Those with bigger body size or higher body fat percentages are generally not as affected by the same dosages as those who are smaller or who have low body fat percentages.
- Health status: If individuals have any physical illnesses, especially those that affect the liver and kidneys, this will change the way their bodies metabolize and excrete drugs and/or alcohol.
Other factors that affect how long drugs stay in a person’s system include:
- What food is in the person’s system
- The specific drug’s half-life
- The dosage taken
- The individual’s metabolism
- The person’s hydration level
A drug’s half-life is the amount of time it takes for half of the drug to be broken down by the liver and filtered out of the body by the kidneys. For example, the National Highway Traffic Safety Administration states that morphine has a half-life of anywhere from 1.5 hours to 7 hours, meaning it takes that long for half of the morphine ingested to be filtered and excreted out of the body. During the next 1.5-7 hours, one half of what is left is filtered and excreted, leaving one-quarter of the original dose left. This process is repeated until the drug has been totally excreted and removed from the bloodstream.
Results of drug tests ultimately depend on when the drug was consumed, and the half-life of the drug. When individuals are administered drug tests, these tests measure the concentration of the drug in the bloodstream in one of the following ways:
- Breath: This type of test is used to detect if individuals have alcohol in their bloodstream and to determine the specific level of blood alcohol concentration (BAC).
- Blood: Blood testing can generally detect a drug for 1-3 days.
- Hair: This test can detect long-term drug use. Drugs can often be detected in hair follicles for up to 90 days.
- Saliva: Most drugs can be detected through saliva for 12 hours to 3 days after ingestion.
- Urine: This test can detect most drugs for about 2-4 days after they were taken, but some drugs may stay in the urine longer, such as marijuana or hallucinogens.
The National Highway Traffic Safety Administration estimates the half-life of marijuana to be between 3-4 days. THC can be detected in urine, depending on when the urine testing is completed. If individuals only use marijuana occasionally, the National Cannabis Prevention and Information Centre states that THC will be detected for 1-5 days after last use. If the person is a regular user, the test can be positive for up to six weeks after last use. In terms of effects, NCPCI states that THC can affect your driving for up to five hours after smoking marijuana.
When people smoke marijuana, the active ingredient – tetrahydrocannabinol (THC) – is stored in fat cells in their bodies to be released slowly into the bloodstream. This may be the reason that long-term users can test positive for an extended period of time after last use. A study published in the medical journal Drug and Alcohol Dependence showed that when regular users of marijuana exercised vigorously, the levels of THC in their bloodstreams increased enough to result in a positive blood test; the test results prior
to exercise were negative.
Other estimates for urine testing windows are:
- Single use of marijuana: 3 days
- Moderate use, approximately four times a week: 5-7 days
- Daily use: 10-15 days
- Long-term, heavy use: 30 days
Cocaine’s half-life, according to NHTSA, is short – less than an hour. However, its major metabolite – a substance that is produced when the body begins to break down cocaine – is benzoylecgonine, which has a half-life of six hours.
Routes of administration for cocaine have the greatest influence on when the effects begin:
- Intranasal use (snorting): almost immediate
- Intravenous use: 15-30 seconds
- Smoking (crack): 5-15 minutes
- Oral: approximately an hour
The effects of cocaine, or the “high,” are relatively short; the National Institute on Drug Abuse states that they last anywhere from 5 to 30 minutes.
It is estimated that cocaine or its metabolites can be detected in urine for 2-4 days after last use.
Opiates: Heroin and Prescription Painkillers
In 2014, in that year’s National Survey on Drug Use and Health, 1.8 percent of individuals aged 12 and older reported using heroin in their lifetime, and an estimated 23 percent of individuals who experiment with heroin become dependent on the drug.
According to NHTSA, heroin has an extremely short half-life of 2-6 minutes. When people ingest heroin, it is then metabolized into morphine and another chemical called 6-acetylmorphine. Morphine has a half-life of anywhere from 1.5 to 7 hours, while 6-acetylmorphine’s half-life is short at 6-25 minutes. Essentially, heroin does not remain in the system for a very long period of time.
Other opiates’ half-lives are:
- Codeine, which metabolizes to morphine and hydrocodone: 1-4 hours
- Oxycodone, which metabolizes to oxymorphone: 4-12 hours
- Oxymorphone: 7-9 hours
- Hydrocodone, which metabolizes to hydromorphone: 3.5-9 hours
- Hydromorphone: 2-9 hours
Some estimates for urine drug testing windows are:
- Codeine: 48 hours after last use
- Oxycodone: 2-4 days after last use
- Hydromorphone: 2-4 days after last use
- Morphine: 48-72 hours after last use
- Heroin, which will be detected as morphine: 48 hours after last use
The specific onset of the “high” after ingesting meth depends on the route of ingestion; however, the onset is generally rapid.
The high can last anywhere from 8-24 hours. Its half-life is approximately 12 hours.
Urine drug testing can detect the drug anywhere from 1 to 72 hours after last use. Blood testing may detect the drug for 4-6 hours, and it can usually determine whether individuals are abusing the drug or on a therapeutic dose. The drug’s metabolites can be detected for up to 2-4 days after people last use the drug.
The National Institute on Alcohol Abuse and Alcoholism describes a standard drink as any drink that contains approximately 14 grams of pure alcohol. This is generally the equivalent of a 12-ounce can of beer, a 5-ounce glass of wine, 8 ounces of malt liquor, or one shot of 80-proof liquor. Mixed drinks or cocktails often contain more than one standard drink.
Although alcohol is absorbed somewhat more quickly than other drugs, it can still stay in the bloodstream for a long period of time. When individuals drink, alcohol builds up in their bloodstream, detected as the blood alcohol concentration (BAC) level. Generally, alcohol is metabolized at a rate of one drink per hour, so a person’s BAC would decrease by approximately 0.015 percent per hour.
Blood alcohol concentration is what is monitored by a breath test when individuals are being evaluated for driving while under the influence of alcohol. NHTSA explains that BAC is a measurement of the weight of the alcohol in a certain amount of blood.
When people drink, alcohol is absorbed through the stomach wall and the small intestines directly into the bloodstream. This quick absorption is what makes it possible to detect the BAC as soon as a half-hour after people have a drink.
However, Blood alcohol concentration is not an exact science, and there are factors that can have an effect on a person’s BAC. For example, females may have higher BAC than males, as women have more fat cells per pound of body weight than men. Since alcohol cannot enter fat cells as readily as it can enter other types of cells in the body, more alcohol stays in women’s bloodstreams.
Drinking quickly will raise BAC more quickly since the body is unable to process the alcohol all at once. In addition, food and other liquids that are consumed affect the time it takes for the body to process alcohol.
Due to all of these factors, there is no set amount of time that alcohol will stay in a person’s bloodstream. If people are aware of how many standard drinks are in the beverages they are drinking, they may be able to calculate the amount of time it will taken on average for the alcohol to clear their bloodstreams. Overall, it is advised that people stay under the Center for Disease Control’s recommended alcohol intake of one drink per day for women and two drinks per day for men.
Binge drinking can be particularly dangerous as it can take many hours for the body to fully process all the alcohol consumed in a session. In some instances, individuals can still be drunk the following morning after a binge drinking session.
Benzodiazepines can be sorted into three categories: ultra short-acting, short-acting, and long-acting. As a general rule, short-acting benzos are processed quickly by the body; users generally feel their effects quickly. Long-acting benzos must be taken for a period of time in order to benefit from their effects.
Each medication in the benzodiazepine family varies when it comes to how quickly effects appear, when the medication peaks in the bloodstream, and how long the medication can be detected on a drug test. The half-life of the drug and how quickly the drug is filtered out of the body directly relate to how long a person will feel the drug’s effect.
Diazepam, which is the generic name for the medication Valium, is a benzodiazepine that is often abused. It is used for the treatment of anxiety and panic disorders. NHTSA explains that while diazepam is rapidly absorbed by the body, it can have a half-life of anywhere from 12 to 44 hours. When it is metabolized by the body, the major metabolite – nordiazepam – has a half-life of approximately 40-100 hours. When a urine drug test is performed, diazepam or its metabolite may be detected anywhere from several days to several weeks after the person’s last use. The package insert for alprazolam – better known as Xanax – states that the half-life of the medication is 6-27 hours.