How does methadone work?

Methadone works by changing how the brain and body perceive pain. More on Methadone’s uses, side effects, and dangers here.

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Methadone is a long-acting synthetic opioid analgesic that works in drug treatment and detoxification programs.  In fact, Methadone is an opioid based medication that’s used to treat addiction to strong opiates like heroin.  How long methadone stays in urine is about 2-4 days after use but how exactly does methadone affect the body and brain? Does methadone have the same effects for everyone? What are the dangers and side effects of methadone use? We’ll explore all those questions here and invite your questions about methadone at the end.

How does methadone affect the brain and nervous system?

Methadone is a prescription drug used both to relieve moderate to severe pain and to help treat opioid dependence.  Specifically, Methadone works by “occupying” the brain receptor sites affected by heroin and other opiates. The result is that methadone blocks the euphoric and sedating effects of opiates while relieving cravings and symptoms associated with withdrawal from opiates.

While highly debated, methadone potentially can cause a euphoric “high” when it binds to the opiate receptors of the brain. However, methadone high effects are less intense than other, similar medications. The decreased addiction liability for Methadone have made Methadone Maintenance Programs a popular form of addiction treatment since the 1960’s.

How does methadone work in the body?

Methadone is excreted slowly so it can be taken only once a day. So what are methadone’s effects on the body?

Methadone slows activity in the brain, and thereby, the body. As a central nervous system depressant, methadone can have some of the following effects:

  • abnormal heartbeat
  • changes in menstrual periods
  • confusion
  • constipation
  • decreased sexual desire or ability
  • fainting
  • flushed or red skin
  • loss of appetite
  • mood changes
  • impaired coordination
  • shallow breathing
  • slowed heart rate
  • snoring
  • stomach pain
  • sweating
  • vision problems
  • weight gain

If you take methadone as directed by a doctor, you’re less likely to suffer any severe side effects. Most serious adverse reactions to methadone are the result of abusing the medication. However, some side effects of taking methadone are emergencies. You should stop taking methadone and contact a doctor or emergency services right away if you experience:

  • chest pain
  • difficulty breathing or shallow breathing
  • fast or pounding heartbeat
  • feeling light-headed or faint
  • hallucinations or confusion
  • hives or a rash
  • swelling of the face, lips, tongue or throat

How fast does methadone work?

Methadone is detectable in the blood within 30 minutes of ingesting the drug, although it doesn’t reach peak concentrations until after about 4 hours. How long it takes for methadone to work can vary between individuals, but it can take several hours before onset of action.

How long does methadone work?

Methadone’s effects can last anywhere from 24-36 hours, depending on the opioid tolerance of the individual. For pain management, it should be taken throughout the day as directed by a doctor. When used to help treat opiate and opioid withdrawal, it’s only given once a day.

What makes Methadone work better

Methadone works best when it’s taken in the doses prescribed by a doctor. Because it can take so long to notice the effects of the medication, it’s important not to assume it “isn’t working” and take more for pain management purposed – this can easily cause an overdose and even death.

Does Methadone work for everyone?

No, methadone is not right for everyone. When taken as prescribed, methadone is safe and effective. But all medicines have risks. The physical effects of methadone must be managed in order to get the maximum benefits of the medication. And because methadone is habit-forming, it’s not always the best choice for someone who wants to quit drugs altogether. Methadone can also have serious side effects in some individuals, including allergic reactions. You may be taking other medications which interact with methadone. Speak to your doctor or pharmacist if you have any questions about methadone being right for you.

How methadone works questions

Please leave us your questions about methadone below. We will try our best to answer your questions ASAP with a professional and personal response.

Reference Sources: CDC: Methadone Maintenance Treatment
Department of Justice: Methadone Maintenance

NHTSA: Drugs and Human Performance Fact Sheets: Methadone
Department of Justice: Methadone Fast Facts
ToxNet: Methadone
Division of Pharmacologic Therapies, SAMHSA: Methadone Safety
About the author
Lee Weber is a published author, medical writer, and woman in long-term recovery from addiction. Her latest book, The Definitive Guide to Addiction Interventions is set to reach university bookstores in early 2019.


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  1. I agree you should find a methadone program near you and get in it with your doctors referral they can help you safely detox off of methadone which is not always easy.

    1. Hi Amy. Call the helpline you see on the website to get in touch with a trusted treatment consultants who can help you find the detox program you are searching for.

  2. I had been taking 15mg of Methadone 3xday for total of 45 mg a day for severe burning chronic pelvic pain. I have been taking it under my doctors orders for 6 months and he also put me on cannibus oil with a small 20 to 1 ratio of THC. My pain started dropping within a few days of only taking .5 mil in a dropper once in the morning and evening. Now that my pain has dropped so much my doctor is reducing my methadone and he had me drop from 45 mg a day to 37 first week…then drop to 30 mg for a he told me we have to be very careful not to drop too much too fast so I am going today to 25mg a day by splitting pills and they are so small to begin with. I am splitting a 10 mg pill into 4 pcs and taking 3 pcs which is 7.5 mg in morning…then a 10 mg pill in afternoon and in evening another 7.5 mg to get to 25 mg day dosage. In a week he wants me to drop to 20 mg day. I believe the CBS oil with small amount of THC is what is helping me drop. I have experienced mild nausea and poor sleep and bad leg aches that wake me all night long but I am very happy to be coming off methadone because of its side effects. Do you have any other ideas regarding how I can get the required dosage other than splitting this 10 mg pill into 4 pcs. My dr suggested going to the pharmacy and seeing if they would split them for me because I an finding I am not getting uniformed pcs…any other suggestions ?

  3. Is it safe to use marijuana with 5mg of prescribed methadone. I have just started using pot and today I started on the methadone.

  4. This is not a professional statement, but comes from very recent personal experience. please consider it. 6 weeks ago I od’d on methadone, if not for Narcan I’d be dead. It was done in ignorance. Ive used 20mg here and there for withdrawal but took 2 more that day. That was too much, if my husband hadn’t woke up for bathroom., I wouldn’t be writing this. Be careful people. I didn’t mean to hurt myself. Research. Talk to doctor. Or leave it alone.

  5. I have 100mg of methadone! I’m Trying To Withdraw From Opiates! How do I take it dosage wise? I have 20/ 5mg pills

    1. Hi Charles. I suggest you speak with a doctor or a pharmacist to help you plan an individualized tapering schedule.

  6. Hello
    My boyfriend is right now in a hospitalized detox program. He is there for 5 days and was told he is being given a tapered dose of methadone. So when I pick him up on Saturday he should need no medication. I was wondering, how does that work? He will be physically fine on Saturday ; no withdrawal symptoms? He is going into a rehab on Monday, so I want to have some kind of insight as to what I will be dealing with on Saturday and Sunday.

  7. My daughter has been on methadone for about 8 years now. It was originally for opiate addiction but for the past. 4-5 years for pain. She also has an alcohol addiction and now has severe liver and kidney damage. Is there a better treatment plan for her then methadone as she is now going to a rehab for alcohol. She seems to be addicted to methadone as well. Cann she get help for her Methadome addictiom

    1. Hello Katherine. I suggest you look for addiction treatment facilities in your area that would treat your daughter’s alcohol problem and her methadone dependence (treatment of these probably won’t happen at the same time). It will be good to have the same professionals go with her as she progresses through recovery. As for the pain management, it’s best to speak to a doctor to find the best course of treatment that will provide pain relief (if still needed).

  8. Good afternoon, I have been on Methadone for over five years for severe congenital lower back pain. Been prescribed 10 mg, tab three times daily and just recently reduced it to twice a day at 10 mg, for a total of 20 mg, per day. Can you please tell me how dangerous it is to my health, is taken methadone 10 mg, twice a day risky for me, teeth, memory, or addition, I did taper off gradually to get at twice a day, and even got down to 15 mg total per day. But my pain and nerve pain was terrible and I did experience some withdraw, but I am now steady with twice a day at 10 mg, per tab, any lower and my pain is intolerable, can you tell me just how dangerous is taking methadone at 20 mg total per day is it, to my health. Is there any other pain medication besides a narcotic that will work?

  9. Hi. I’m currently starting a,detox from heroine. I have a child so it’s difficult. I’m in possession of a bit (approx60ml) methadone. I wanted to use it 30ml per day to help reduce withdrawal symptoms. Will this reduce the withdrawals and allow me to detox, or am I just adding more opiates to postpone my withdrawls and then after 5 days I will get a full on heroine withdrawl? I’m hoping that the methadone will hold the withdrawls for a couple of days, whilst I still detox from the heroine. Then I will be over the worst? Thank you, got my self into this situation and am desperate to get my life back

  10. Hello Amy. From my reading, weight increase in methadone maintenance treatment patients is not considered a direct side-effect of the medication, because it is not possible to differentiate between a drug effect and changed behavioral eating that can occur. For more reading on this, use the search term: methadone weight gain

  11. What long term withdrawals does methadone have in the nervous system? With a person who went through a medical detox after being on methadone for 9 yrs plus 4 yrs of oxycotin before that. It’s been almost 4 months and I’m having problems with pain and nerve type problems that move everywhere.
    Any help would be greatly appreciated!

  12. I savour, result in I found just what I used to be taking a look for. You’ve ended my 4 day long hunt! God Bless you man. Have a nice day. Bye

  13. how do you know when you have reached your correct dose of methadone for opiate dependence? i am in an excellent recovery program now

  14. Speaking as a pharmacist and from experience in Lortab addiction, it sounds like he’s doing great with what he’s done so far with the methadone. I would not recommend switching to Percocet or Vicodin or any other hydrocodone. There would be no benefit in switching as they are both addictive, and the hydrocodone is the more dangerous of the two drugs with regard to overdose and other side effects. I would recommend Suboxone if he truly can’t reduce any further on it’s own. It’s not cheap, and is still somewhat addictive, but not nearly to the extent that methadone and hydrocodone are. Suboxone helps reduce withdrawal effects while allowing the receptors on your brain (the ones that are elevated due to the addiction) to dwindle back down to normal. It’s much easier to come off that the hydrocodone or methadone. Hope this helps!

  15. Hi Karen. I must add here that it is ALWAYS advisable to taper or withdraw from methadone under medical supervision. Even if it’s a phone call. I’ve found some information for you and list it here:

    Hydrocodone and oxycodone have the potential for euphoric effect (feeling high), so may not be good options for replacing methadone. Safe tapering of methadone may follow several general paths (2 to 3 week tapering regimen should be adequate in most cases)
    o Reduce the each daily dose by 10%
    o Reduce the dose by 20% every 3-5 days
    o Reduce the dose by 25% per week
    o Avoid reducing the daily dose by > 50% at any given interval

    You can learn more by searching Google using this search term: “ taper methadone protocol” However, I would strongly urge your boyfriend to call or visit his prescribing doctor for information and support.

  16. My boyfriend is trying to wean himself off of oral methadone he has been prescribed for pain. He is in between jobs and has no insurance and while he SHOULD be doing this under dr care he insists on getting it over with on own. The question I have is whether it would be easier for him to try to switch to hydrocodone or oxycodone (he has Percocet 5 mg and 10mg vicadin Rx at home) or to stick with lowering and spreading out doses of the methadone which is my guess since it is much longer acting. Dr Recently lowered him from 30 mg/ day – 10 in AM and 20 in PM to 20mg / day and he has gone down to ten now but is having trouble with going down to 5. Any advice is welcome.

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