How Long Do Drugs Stay in Your System?
Like foods, medications, and other substances you ingest, drugs and alcohol must be processed by your body before they’re eliminated from your system. The effects of drugs may last for hours, days, or weeks, depending on several factors including the following:
- The type of drug you take
- The amount of the drug you use
- The frequency of your drug use
- Your general health
- Your metabolic rate
- Your gender
- Your height and weight
The digestive organs, respiratory organs, liver, and kidneys are involved in the metabolism or elimination of many of the drugs you take. Drugs can be detected in your body by testing your breath, blood, saliva, sweat, breast milk, urine, or hair. Even ear wax and umbilical cord blood can be used to detect substance intake.
Why Is Drug Testing Important?
Drug testing has become increasingly commonplace among employers, hospitals, and schools, primarily because positive urine drug screen results tend to accurately predict worse outcomes in these environments. Employers may conduct drug testing as a pre-screening measure. Hospitals often test for the presence of drugs after an accident, assault, or suicide attempt. Schools may test students who participate in sports or other activities outside of the classroom. Drug testing is routine in the military, where active-duty service members must undergo screening on a regular basis.
The National Institute on Drug Abuse notes that drug testing is often used for the following reasons:
- To discourage drug and alcohol abuse
- To protect a company or institution’s financial resources
- To detect potential threats to an individual’s health
- To detect threats to the security of a company, school, or political entity
- To protect others from the effects of drug or alcohol misuse
- To identify signs of drug abuse in order to provide early intervention
Now that drug screening has become more prevalent, the chances are good that you’ll be required to take a test at some point in your life. Some companies or agencies only perform tests on a scheduled basis, but many will require random screening if there’s reason to believe that you’re abusing drugs or alcohol. Samples of your urine, blood, breath, hair, or saliva may be analyzed to determine whether you have drugs or alcohol in your system. While some drugs are eliminated from your body very quickly, others may be detectable for weeks or even months after use.
The Most Common Types of Drug Tests
You’ve probably heard of the breathalyzer test for alcohol and urine screening for certain drugs. But there are actually several major types of drug tests:
- Urine test. Urinalysis for drug screening is fast, convenient, and generally accurate, which makes this a popular type of test for employers and law enforcement agencies, especially when random testing is required.
- Blood test. Blood tests take longer to develop than urine tests, but this method is very effective at detecting concentrations of alcohol and other drugs. Blood testing can determine your level of intoxication but only for up to 24 hours after you’ve been drinking.
- Breath test. Most of the alcohol you drink is processed by your liver, but as the alcohol is being metabolized, traces are eliminated in your breath and urine. Law enforcement agents can use a device called a breath analyzer to detect the level of alcohol in your breath.
- Saliva test. The saliva holds traces of alcohol, hormones, and other chemicals that can indicate drug use. Saliva testing is no longer as popular as blood or urine testing. Drugs can usually be detected in the saliva for only a few hours to a few days.
- Hair test. Analyzing the hair for chemical traces may be the most accurate way to test for long-term drug use. Because hair grows slowly (only about 0.5 inches per month), traces of certain drugs can be detected for months. Hair analysis requires more processing time than urine or blood testing.
When you drink, your liver metabolizes about 90 percent of the alcohol you consume. The remaining 10 percent is eliminated in your breath, blood and urine. For most people, one ounce of alcohol will produce a .015% blood alcohol concentration, meaning 0.15 grams of alcohol for every 100 mL of blood. If you drink enough to raise your blood alcohol concentration to 0.015%, it will take one hour for your body to eliminate the alcohol. Blood alcohol concentration can vary according to gender, weight, the amount of alcohol you drink, your activity level while drinking and the presence of food in your system. As a general estimate, alcohol may stay in your system from 1 hour to 12 hours.
Alcohol can be detected in breath, blood, saliva, or urine, but the most common ways to screen for alcohol use are breath and blood tests. A breath analyzer (or “breathalyzer”) is a portable device used to measure the concentration of alcohol in your breath. When you exhale into the mouthpiece of a breath analyzer, the machine estimates the amount of ethanol, the active ingredient in alcoholic beverages, in the exhalation. Breath analysis can be performed in workplace settings, in schools, or in the field by law enforcement agents.
A preliminary breath test may be conducted during a traffic stop if an officer has reason to believe that you’re violating the law while under the influence of alcohol. If the alcohol in your breath exceeds the legal limit, you may be arrested and required to take a blood test to confirm your exact blood alcohol concentration (BAC).
Amphetamines stimulate the central nervous system, giving you a sense of energy and sharpened mental focus. Amphetamines have a high potential for abuse and dependence. Black beauties, crosses, reds, and speed are some of the street terms for these drugs. The effects of a single dose of amphetamines may last for only two to four hours, but the drug can be detected in your urine for up to 48 hours. Traces of amphetamines may be detected in hair for up to 90 days.
Barbiturates suppress the activity of your central nervous system. This class of drugs is prescribed to promote sleep, prevent seizures, and reduce anxiety. Barbiturates may be used for non-medical purposes to achieve a sedative effect. Long-acting barbiturates like phenobarbital may stay in the system for up to 140 hours, while short-acting barbiturates like Seconal may stay in the system for up to 40 hours. Short-acting barbiturates may be detected in the urine for up to five days, while long-acting barbiturates may be detectable for as long as three weeks.
Benzodiazepines act on the central nervous system by affecting the brain’s response to the neurotransmitter GABA. These drugs are prescribed to control anxiety, promote sedation, and prevent muscle spasms and seizures. Benzodiazepines like Valium, Xanax, and Ativan are often misused for non-medical purposes and have a high potential for abuse. The length of time that a benzodiazepine stays in your body will depend on the potency of the drug, the dose, your body weight, and the frequency of dosing. Drugs like Xanax or Valium may be detected in urine for up to seven days after the last dose, but in general, the detection time frame for benzodiazepines1 is two to five days in the urine.
Cocaine is a powerfully addictive central nervous system stimulant that acts on the brain to produce a rush of elation combined with a surge of energy. While smoking cocaine (usually in the form of “crack” cocaine) provides the most rapid effect, snorting or injecting cocaine takes effect on the brain within a matter of minutes. Within 15 minutes after use, blood levels of cocaine generally reach their peak. After that time, blood levels decline. Cocaine can be detected by blood tests for about 12 hours after you use the drug. If you use cocaine on a regular basis, the byproducts of the drug may be detected in your urine for up to two weeks after your last use. Hair analysis can reveal traces of cocaine use for three or more months after use.
Heroin is a highly addictive narcotic derived from the opium poppy. The drug produces feelings of euphoria and sedation within a matter of seconds or minutes, depending on how you take heroin. Intravenous injection provides the fastest rush, delivering the drug to the brain within seconds. Reaction times are longer when the drug is smoked or snorted. The body eliminates heroin quickly—within eight minutes. Depending on your age, weight, amount used, and frequency of use, heroin can be detected in urine for up to 48 hours.
Marijuana comes from the Cannabis sativa plant, and the active ingredient in this sedative drug is tetrahydrocannabinol, or THC. Marijuana may take effect within 3 to 8 minutes of use, but THC remains in the system much longer, even in casual users. Unlike smaller and more water-soluble drugs like heroin or cocaine, marijuana’s active ingredient is stored in your body and can be detected for up to 4 weeks in long-term users. Your body stores THC in fat cells, which release the chemical slowly into the bloodstream. In casual users, byproducts of cannabis use can be detected in urine for up to 5 days. In chronic users, cannabis use may be detected for up to 30 days. If marijuana is taken orally in food, the detection window for urine testing may be extended.
Methamphetamine, also known as meth, crank, crystal, or speed, is a stimulant that acts on the central nervous system, activating the release of the neurotransmitters dopamine, norepinephrine, and serotonin. Like cocaine, meth produces feelings of euphoria, heightened energy, and intensified focus, but the effects of meth may last longer. Levels of methamphetamine byproducts in your system peak at about 12 hours. Meth may be detected in urine for 2 to 4 days after use. Traces may be found in hair for several months after use.
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