How Long Does Methadone Stay in Your System?

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Methadone is an opiate analgesic—a narcotic pain medication that's sometimes prescribed for people who aren't getting enough relief from another analgesic. Like other opioids, it works by changing the way the brain and the rest of the nervous system respond to the sensation of pain.


Interestingly, methadone is used most often to help prevent withdrawal symptoms in people who've become addicted to other opiates such as heroin, and who are undergoing treatment to break that addiction. Withdrawal from a drug like heroin can be excruciating. Methadone helps to ease the process by producing sensations that are similar to the effects of the drug.

High Risk of Overdose

Methadone is a powerful medication and it remains active in the system long after its analgesic effects wear off. According to data from the U.S. Food and Drug Administration, pain relief from methadone can last from 4 to 8 hours, but it can take anywhere from 8 to 59 hours for the drug to fully clear from the body.

What this means for someone taking methadone for pain relief is that they may think they need to take a second dose before the first one has completely cleared from their system, which can lead to an overdose. This can result in a coma or even death, so it's important to recognize the symptoms of a possible methadone overdose.

Symptoms of an overdose from methadone include:

  • Slowed breathing
  • Sleepiness
  • Muscle weakness
  • Cold, clammy skin
  • Changes in the size of pupils (they can become narrower or wider)
  • Slowed heart rate
  • Inability to respond or wake up

If you think someone has overdosed on methadone, get emergency help right away. If caught early, methadone overdose may be reversed with a drug called Narcan (naloxone).

The American College of Medical Toxicology notes that medical providers should be cautious when prescribing methadone for pain relief. Methadone should not be prescribed on an as-needed basis.

It's important to know how long methadone can stay in the body in order to prevent an accidental overdose. Methadone affects the central nervous system (CNS). A dangerous drug interaction could occur with other substances that affect the CNS if methadone has not fully left a person's system.

Dangerous drug interactions could occur with:

  • Alcohol
  • Antidepressants
  • Other narcotic pain relievers
  • Medications for anxiety, nausea, or mental illness
  • Muscle relaxants
  • Sedatives or sleeping pills
  • Tranquilizers
  • Any type of street drug

The lethal dose of methadone for an adult may vary depending on their level of dependence and/or tolerance, but a person should never take more than the dose that was prescribed by their doctor. For a regular methadone user, the fatal dose may be 200 mg or more, while a less tolerant person could overdose with as little as 30 mg. Methadone builds up in the system over time, which means that even a prescribed dose could lead to an accidental overdose. Older patients should be prescribed a lower dose since methadone metabolizes in their bodies at a slower rate.

According to the Centers for Disease Control and Prevention (CDC), methadone is responsible for over one-third of all overdose deaths from prescription painkillers.

If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area.

For more mental health resources, see our National Helpline Database.

Testing for Methadone

Estimating how long methadone is detectable in a person's body depends on several factors, such as age, weight, percentage of body fat, how active a person is, and the level of hydration. Some health conditions can play a role in the rate at which drugs are metabolized by the body. The length and frequency of methadone use, as well as the dosage, also factor into the length of time it might be detectable.

A combination of factors, including things like the user's age, liver function, pregnancy status, metabolic rate, frequency of drug use, the dose taken, and whether other drugs were taken at the same time, all interact to affect how long a period of time the methadone will remain in the user's system.

There are some unspecific estimated ranges of times, or detection windows, during which methadone can be detected by various testing methods. In urine, this window is anywhere from one hour to two weeks. A blood test for methadone can detect the drug for 2 to 3 days and a saliva test about the same length of time.

Like many other drugs, methadone can be detected with a hair follicle test for at least 90 days, and possibly, as long as six months depending on the frequency of use.

11 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Buddy T
Buddy T is an anonymous writer and founding member of the Online Al-Anon Outreach Committee with decades of experience writing about alcoholism.