Methadone is a drug prescribed to treat opioid use disorders and chronic pain. The methadone half life refers to the amount of time it takes for fifty percent of the drug to leave your system, which can vary due to many factors.
Key Facts
- Methadone is used as part of a medication assisted treatment.
- Half life determines how long methadone stays in your system.
- Methadone specific drug tests can be used by testing urine, saliva, blood and hair.
- Numerous factors can affect methadone half life.
Methadone Half Life Basics and How Methadone Works
When taking any medicine, it is important to understand the basics, such as how it works in the body, how long it remains in the body and what to expect. Knowing this can help you better prepare for any side effects that you may experience.
What Methadone is and Why It’s Used
Methadone is a long acting synthetic opioid agonist prescribed for opioid use disorder. It is one option in a medication assisted treatment (MAT) program. Methadone reduces cravings and withdrawal symptoms. It also helps to stabilize mood and improve one’s ability to function.
Some doctors may also prescribe it for chronic pain.
In most methadone maintenance programs, doses are taken daily and are administered in person at a methadone facility. It is available in liquid, tablets or wafers through a licensed opioid treatment program (OTPs).
What is Half Life and Why is Methadone’s So Long?
Half life refers to the time it takes your body to eliminate about 50% of a drug. Methadone’s half life is long and variable. It may remain in your system for 8 to 59 hours or more, much longer than most other opioids.
In comparison, heroin has a half life between two and six minutes.
Because methadone is long acting and stored in body tissues, levels can build up over several days, which is helpful for cravings but increases the risk of overdose if doses are increased too quickly.
How Long Does Methadone Stay in Your System
How long methadone stays in your system varies for each person and is based on their rate of metabolism and other factors.
How Long Does Methadone Stay in Your Body After a Dose or After Stopping
Methadone typically has a one day half life. On average, it will clear in 24 hours; however, it can take up to four or five days to be fully cleared.
Individuals who have used methadone long term will have a detectable amount of the drug in their system for longer than a person who used it short term.
When you stop taking methadone, the effects of the drug don’t stop immediately. For example, pain relief may last four to eight hours after the last dose is administered.
Moreover, symptoms of withdrawal and cravings typically do not start for 12-48 hours after the last dose.
Methadone Drug Testing & Detection Windows
Whether you are getting a drug test for employment or for treatment purposes, it is essential to understand how they work and also how they differ.
Urine Drug Screens for Methadone
Standard employment drug screens do not normally detect methadone, as they typically only look for morphine or heroin. Methadone detection requires a specific methadone (MTD) or EDDP urine test.
Methadone and its primary metabolite (EDDP) commonly show up in urine for about three to ten days after the last dose. If you take a high dose or have been using it for a long time, it may be detectable up to approximately two weeks.
Blood and Saliva Detection Times
Blood and oral fluid (saliva) tests for methadone are often used in hospital, overdose, or accident settings, not commonly in routine screenings.
Methadone can usually be detected in blood and saliva within 30 minutes to a few hours after dosing, with a typical detection window of about one to two days.
If you take high doses, have a slow metabolism, liver disease or overdose, it can extend the amount of time it is detected in blood/saliva. It can also increase the risk of sedation and respiratory depression even after the visible effects fade.
Hair Tests and Long Term Detection
Tiny amounts of methadone and its metabolites are deposited in hair as it grows. When you take a hair follicle test, it can detect long term use of methadone, not a recent intoxication.
A standard 1.5-inch hair sample can often show methadone exposure for up to about 90 days, depending on growth rate and lab cutoffs.
Examples of when hair testing may be used are in legal, child welfare or compliance settings and are typically for documenting a pattern of methadone use or misuse over months.
Factors That Affect Methadone Half Life
Many factors can affect the half life of methadone in your system. Besides metabolism, these include your dose, how long you have been taking it, your physical health, age, and if you are taking any other drugs, including prescriptions and illicit substances.
Dose, Frequency of Use, and Length of Treatment
If you take high daily doses of methadone or get your doses more frequently, it can affect its half life. This happens because methadone accumulates in fatty tissues, causing it to remain in the body longer.
If your body has become used to having methadone in its system, which can easily happen with long term maintenance, this can affect its half life. The way you metabolize methadone will be different from people who have just started using the drug.
Furthermore, the longer you’ve been on methadone maintenance, the more likely your urine and hair follicle tests will detect the substance, even after you stop taking the medicine.
Health, Age, Liver Function and Pregnancy
Older adults, people with low body weight or those with chronic health issues may have slower elimination of the drug and be more sensitive to side effects like drowsiness and breathing problems.
Methadone is processed mainly in the liver. If you have diseases like cirrhosis, hepatitis or other problems with your liver, it can slow the clearance of methadone and raise blood levels.
On the other hand, someone who is pregnant, especially in the second or third trimester, has a faster metabolism than a person who is not pregnant.
In such cases, your doctor may need to adjust doses to prevent maternal withdrawal and protect the fetus.
Other Medications, Alcohol and Overdose Risk
Medication interactions can occur when you are taking methadone. Medicines like antibiotics, antifungals, seizure meds, HIV treatments and some antidepressants can either speed up or slow down methadone metabolism via your liver enzymes.
Mixing alcohol and drugs can also cause problems. Combining methadone with alcohol, benzodiazepines (like Xanax, Valium), sleep aid or other sedating drugs dramatically increases the risk of respiratory depression and overdose due to its long half life.
You may even experience methadone toxicity or overdose when you combine methadone with other substances. Warning signs of methadone toxicity include extreme drowsiness, slowed or shallow breathing, confusion, blue lips or fingertips or being hard to wake.
If any of these occur, seek immediate emergency medical care.
FAQs About Methadone Half-Life & Drug Tests
The body naturally detoxifies medicines through excretion. There aren’t many ways to speed up this process. However, staying hydrated, eating well and getting regular exercise support overall liver and kidney function, but only modestly impacts methadone clearance rates.
Detox drinks, extreme exercise, flushes and cleansing regimens or home remedies do not reliably shorten detection time and can be risky or trigger withdrawal.
It is never a good idea to quit taking methadone abruptly or without medical supervision. The safest way to lower methadone levels or taper off is to work with your prescribing clinician or opioid treatment program on a gradual, medically supervised plan.
Methadone is a full opioid agonist with a long, variable half life. Buprenorphine, which is the main ingredient in Suboxone, is a partial agonist with a more predictable half life and a “ceiling effect” on respiratory depression.
Both methadone and buprenorphine usually require specific drug test panels; they may not appear on a general opioid screen.
Choosing between methadone, Suboxone or other medications for opioid use disorder depends on your history, stability and medical conditions. Any changes to your medication should always be made under your medical provider’s supervision.
Find Treatment Near You
To learn more about methadone, starting a methadone program or how to safely stop using methadone, reach out to someone for help today.
You can use the Rehab.com online directory to find treatment centers in your area. You can also filter the directory by location, level of care, insurance and special programs.
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