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.

The High Risk of Methadone Overdose

Methadone is a powerful medication and it remains active in the system long after its analgesic effects wear off. The U.S. Food and Drug Administration states that while pain relief from methadone can last from four to eight hours, it can take between eight and 59 hours for the drug to fully clear from the body.

This means that someone who's taking it for pain relief may think they need to take a second dose before the first one has completely cleared from his system, potentially causing him to take too much of the drug. This can lead to a coma or even be fatal, so it's important to know the early symptoms of a methadone overdose. These include slowed breathing; sleepiness; muscle weakness; cold, clammy skin; changes in the size of pupils (they can become narrower or wider); and slowed heart rate. 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.

Preventing an overdose of methadone is one reason it's important to know how long it can stay in the body. Another is that because it affects the central nervous system, certain other substances that affect the central nervous system should always be avoided if there's any chance there's methadone in the system. These include alcohol; antidepressants; other narcotic pain relievers; medications for anxiety, nausea, or mental illness; muscle relaxants; sedatives; sleeping pills; tranquilizers; and any type of street drug.

The official lethal dose of methadone for an adult who isn’t dependent is 25 mg. For a regular methadone user, the fatal dose may be 200 mg. Methadone builds up in the system, and even a prescribed dose could be an overdose. Symptoms of methadone overdose may take up to ten hours to appear. Methadone is responsible for over one-third of all overdose deaths from prescription painkillers, or as many as four out of ten prescription painkiller overdose deaths involve methadone.

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 two to four days. A blood test for methadone can detect the drug for up to 24 hours 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.

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  2. Grissinger M. Keeping Patients Safe From Methadone OverdosesP T. 2011;36(8):462-466.

  3. Roxane Laboratories Inc. Methadone Hydrochloride Cl Tablets USP 5mg, 10mg. (Dolophine HCl CII). 2006.

  4. American College of Medical Toxicology. ACMT Position Statement: The Use of Methadone as an AnalgesicJ Med Toxicol. 2016;12(2):213-215. doi:10.1007/s13181-015-0532-6

  5. United States Government Accountability Office. Methadone Associated Overdose Deaths. Factors Contributing to Increased Deaths and Efforts to Prevent Them. 2009.

  6. Center for Substance Abuse Treatment. Appendix B. Urine Collection and Testing Procedures and Alternative Methods for Monitoring Drug Use. In: Substance Abuse: Clinical Issues in Intensive Outpatient Treatment. Rockville, MD: Substance Abuse and Mental Health Services Administration; 2006.

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