Back to Sobriety: How Long Different Substances Stay in Your System

Some people are interested in learning how long a substance stays in the body to know when they can safely return to work, operate machinery, or drive a car.  Others may be concerned about their ability to pass a drug test for work, school, or other purposes.  Whatever your reason for being interested in this information, this article will explain the factors that determine the duration of the presence of some substances in the body; it will also provide general time-frames that a number of drugs remain in a person’s system.

What determines how long a drug is in your body?

Importantly, there is a significant amount of individual variation in terms of how long a drug stays in your body (Read Response to Substances: Why It Varies By Person).

Dose/Body Weight – Consider alcohol consumption.  A man who drinks 5 drinks in an hour will have a higher blood alcohol level for much longer than a man who has similar bodily characteristics and consumes 1 drink in an hour. This occurs because the liver can only metabolize the alcohol at a certain rate.  However, a 250 pound individual will process alcohol differently than a person who weighs 100 pounds; the larger the person, the greater the blood volume, which makes alcohol more dilute in the person’s system.  Additionally, people who are physically bigger (usually) have larger livers and, by extension, more enzymes to process substances, which may translate into the body clearing out the drug sooner.  Likewise, long-term users of substances like meth will require longer periods of time to eliminate the drug compared to someone who has only taken a single dose.

Method of Administration – How a drug is delivered into the body also plays a role. An extended-release prescription medicine—when taken as directed—will take longer to enter and exit the system than if that drug were to be crushed and snorted.  In general, delivery “speed” from fastest to slowest is as follows: intravenous injection (directly into the bloodstream), smoking (into the blood via the diffusion in the lungs), snorting (processed through mucous membranes in the nose), and oral (digested by the stomach).

Metabolism – Metabolism, or the processes that convert the drug into compounds that can be eliminated from the body, can vary from person to person.  Liver or kidney diseases can make it difficult for a person to metabolize a substance.  In a more specific example, an alcoholic who has developed cirrhosis of the liver will have more difficulty metabolizing the alcohol than will a healthy counterpart.

The Drug’s Half-Life – All substances have half-lives, which can be loosely defined as the time it takes for the drug’s concentration to decrease by half (say, from 1.0 mg to 0.5 mg to 0.25 mg, etc.).  Generally speaking, it takes a cycle of 4 to 5 (but possibly up to 7 or more) half-lives for a substance to be eliminated from the body.  Here is a list of some drugs and their approximate half-lives in parentheses: meth (10 hours), Vicodin (4 hours), Xanax (12 hours), heroin and its metabolized forms (6 hours), cocaine (1 hour), ecstasy/MDMA (8 hours), OxyContin (4 hours), PCP (21 hours), and Suboxone (25-40 hours).

Distribution/Tissue Solubility: Whether a drug remains sequestered in body tissues can also determine how long it will be detectable in drug screens.  Perhaps the best known example of a long-lasting drug is marijuana; the THC gets absorbed into fat cells and, for this reason, it can take anywhere from 30 to 60 days for the body to completely excrete it.

How Can I Tell if a Drug Is Still in My System?

Even if you are not experiencing known effects of the drug, it may still be present.  You can visit your doctor’s office and request a blood test or you could order a home drug screening kit; some of these home kits test for specific drugs whereas others will test for a spectrum of substances (Read Home Drug Testing Kits: Should You Try Them?).  However, if you are worried about an upcoming drug screen, you may be struggling with addiction (Read Self-Evaluation: Is There a Problem?). eDrugRehab can give you the help you need to break the cycle. Call now!