How Long Does it Take for a Drug to be Cleared from the Body After Cessation?

Quitting addictive substances is one of the best decisions you can make for yourself and your loved ones. Embracing sobriety can help you regain stability in your life and achieve your personal goals. Detox is often the first step in this process, involving abstaining from the substance long enough for it to leave your system. This article explains how long it takes for a drug to clear from your system, whether it’s still detectable by a drug test during this period, and what factors can influence this duration.

How Long Will a Drug Stay in My System?

A drug remains in your system until your body naturally eliminates it through detoxification.[1] During this process, the drug is transformed into a non-toxic form by the liver and is processed for removal. However, byproducts of the drug, called metabolites, may remain in the bloodstream for hours, days, weeks, or even months after the last use.[2] These metabolites can be identified using drug screening tests that analyze various bodily fluids, such as saliva, urine, blood, and sweat.[3] This helps determine if the person has used drugs within a certain period.

What is an Elimination Half-Life?

An elimination half-life is the period required for a drug to be metabolized or eliminated in the body, during which only half of its original amount remains.[4] This duration can differ across drug classes and is affected by factors like age, weight, health status, dose, and route of administration. Some drugs have a set elimination half-life, regardless of how much of it you take. For instance, meloxicam has an elimination half-life of 20 hours.[5] Even if someone takes three times the dose, the elimination half-life is still 20 hours. However, taking doses too closely together can increase the elimination half-life by several hours, as it reintroduces more of the substance to the system before the last dose is eliminated.

How Many Half Lives Does it Take for a Drug to Exit the System Completely?

The National Library of Medicine states that it generally takes approximately four to five half-lives for a drug or substance to be cleared from the body.[4] The variation in the number is due to differences in how quickly different medications are metabolized—some are processed more slowly, while others are eliminated faster. For example, meloxicam, with a 20-hour elimination half-life, would take approximately 100 hours to completely clear the system. This includes most of its metabolites. Note: Individuals with impaired liver or kidney function may process the medication more slowly. In these cases, the exact time for the medication to completely exit the system is uncertain.

Typical Half Lives of Commonly Addictive Drugs

Each substance has its unique elimination half-life, which depends on its classification and route of administration. The following is a list of the most commonly used substances and their elimination half-lives.

• Stimulants:[6] The elimination half-life for short-acting stimulants is nine hours, and for long-acting stimulants, it ranges from nine to 13 hours.
• Benzodiazepines:[7] Benzodiazepines are categorized as short-acting, intermediate-acting and long-acting, each having its own elimination half-life. They are as follows: short-acting, 1 to 12 hours; intermediate, 12 to 40 hours; and long-acting, 40 to 250 hours.
• Opioids:[8] Opioids are divided into two categories: ultra-short and ultra-long. The elimination half-life of ultra-short acting opioids is 0.6 hours, and 24 to 36 hours for ultra-long-acting opioids.
• Cannabinoids:[9] A cannabinoid is a product that contains the active compound THC. These products have an elimination half-life of one to three days in casual users. However, this time ranges from five to 13 days in chronic users.
• Alcohol:[10] Alcohol has an elimination half-life of four to five hours. However, according to the Cleveland Clinic, alcohol’s elimination half-life can vary depending on how much the person drinks and how frequently.[10]

Factors that Influence the Elimination Half-Life of a Drug

There are a number of factors that can result in a long half-life.[4] These include:[11]

• Age
• Formulation
• Kidney impairment
• Liver impairment

Some factors can also decrease the elimination half-life of a drug. These factors include:

• Increased blood circulation due to blood transfusion
• Receiving intravenous hydration
• Medical conditions that cause increased liver enzymes
• Increasing blood volume[12]

Some people might receive emergency fluids or a gastric lavage to remove a substance from the body, especially in cases of overdose. These treatments, along with activated charcoal, can decrease the substance’s elimination half-life.

How are Drugs Detected in the System?

Even after a drug is fully eliminated from the system, it may still be detectable in a drug screening. The following reflects the different amounts of time during which drugs are detectable in the system using various collection methods.

Urine Drug Tests

Urine drug tests are the most commonly used since there are numerous advantages to using them.[14] These include: [14] 

• Detecting higher concentrations of a drug and its metabolites
• Offering greater accessibility of point-of-care tests (POCTs)
• Providing a heavily researched medium with a lower risk of false results

However, despite the above-listed advantages, there are a number of disadvantages that include:[14]

• A shorter drug detection window
• An easier-to-adulterate medium
• An easily substitutable testing medium

Urine tests can detect drugs and their metabolites in the urine for 1.5 to four days. However, in chronic users, they can still be detected for up to a week.[15]

Blood Drug Tests

Unlike a urine test, a blood drug test requires professional collection and administration. However, the results are much harder to manipulate than those of a urine test, making it a more reliable testing method for many businesses. There are also some disadvantages, which include:[14]

• A limited detection window
• An increased risk of developing or contracting an infection
• An invasive collection method
• Needing a trained medical professional to collect
• Needing easily accessible veins

Blood tests have the ability to pick up drugs and their metabolites for one to two days.[15]

Hair Drug Tests

The most commonly used non-invasive drug test is a hair collection screening. This testing method offers a wider detection window than urine and blood screenings with superior accuracy. Other advantages to using hair drug screening tests include: [14]

• Observed collection
• Ease of storage and transportation
• Tracks changes in drug use over time
• More difficult to adulterate
• Easily accessible sample

Disadvantages include:[14]

• Overall cost and screening time
• Inability to detect drug use within 10 days of testing
• Can only be administered in labs with hair detection tests
• Harder to detect traces of tested substances in light colored hair
• Risk of environmental contamination
• Cannot test individuals without hair

Hair strands hold drugs longer than saliva, urine or blood. [15]

Saliva Drug Tests

Oral fluid is a convenient matrix for testing the presence of drugs. It yields advantages such as a reduced risk of adulteration, the ability to detect residual drugs, and same-day collection.[14] However, the disadvantages of using saliva as a testing matrix are numerous and include:[14]

• A shorter window of testing
• Stimulant usage leading to inaccurate test results
• Smaller specimen volume
• Residual drug contamination
• Requires supervision

Drugs are detectable in saliva for five to 48 hours. [15]

Drug Detector Factors

Some medications and substances can cause a person to fail a drug test because they have a similar chemical structure to the substance being tested. This similarity can lead the test to mistakenly identify these substances as the target drug. These include:[16]

• Antihistamines: May trigger false positives for opioids or PCP.
• Antidepressants: Medications from this class may trigger a false positive for amphetamines or methamphetamines.
• Decongestants: May yield a false positive for amphetamines and methamphetamines.
• NSAIDS: Can trigger a false positive for barbiturates, THC or benzos.
• Cough suppressants: Can trigger a positive screening for methadone.
• Poppy seeds and Coco tea: May result in a false positive for THC-containing or cocaine.

If you have taken any of the substances listed above and receive a false positive on a drug screening, inform the testing center; they might conduct a different test or repeat the test.

Will I Experience Withdrawal Symptoms Once the Addictive Drug Leaves My System?

This depends on the substance used. If you take an addictive substance at abusive levels, such as higher than prescribed doses, or by mixing it with another addictive substance, you may become physically dependent.[17] This means you will experience withdrawal symptoms, like physical pain, agitation, or anxiety, when the drug is not in your system. This occurs due to chemical changes in the brain’s reward and motivation centers.[18] When you use an addictive substance, your brain releases the feel-good hormone dopamine, leading to a feeling of euphoria. As dopamine levels drop, you start to feel normal again.[18] If this isn’t a desired state, it might cause the person to use the drug again. Over time, the brain gets used to this dopamine release and will encourage the user to take the drug again to feel better. Simultaneously, the extended amygdala drives unpleasant sensations to motivate the person to find the drug and use it again.[19] Afterwards, the person is rewarded with another flood of dopamine. Unfortunately, that initial euphoric feeling can’t be experienced multiple times. As a result, higher doses or increased use of the substance are needed to achieve a similar dopamine response. This is known as tolerance.[19] When tolerance develops, it may lead to a diagnosis of substance use disorder.[20] A full-blown addiction develops if a substance use disorder remains untreated long enough to cause additional changes. These changes include:[21]

• Continuously using the drug, even though it’s causing or worsening a physical or mental health condition.
• Continuing to use the drug, despite not wanting to.
• Using the drug in a risky situation can cause injury to yourself or others.
• Having a preoccupation with using the drug even when you’re not using it.
• Isolating from social events due to using or recovering from drug use.
• Experiencing withdrawal symptoms when trying to stop.
• Experiencing tolerance (needing more and more of the drug to feel its effects).
• Isolating from family and friends.
• Continuing to use the substance despite it causing problems in your social life.
• Falling behind in responsibilities at work, home, or school because of drug use.

Getting Help for Drug Abuse

If you find yourself using drugs to avoid the discomfort of withdrawal, you may have a substance use disorder. Experiencing withdrawal when trying to stop can make it difficult to quit, but there are evidence-based programs that can help you abstain from drug use and prevent relapse. At Southeast Addiction Center TN, we offer detoxification services that allow you to safely and comfortably abstain from the addictive substance, along with comprehensive treatment programs targeting the root causes of the addiction. These treatment options include behavioral therapy, yoga, and group therapy, offered in inpatient, outpatient, and partial hospitalization programs. These programs aim to help you maintain long-term sobriety. To learn more about how our programs can guide you toward lasting sobriety, please contact us today. We are here to support you every step of the way.