DESCRIPTION / DEFINITIONS: Methadone is a synthetic opioid prescribed as a pain killer and as a drug designed to curb cravings when undergoing Medication Assisted Treatment (MAT) for opioid dependency and addiction.

ABUSE: Methadone is a Schedule II drug, meaning that it has a high potential for abuse and may lead to severe psychological or physical dependence. See Black Box warning below.

ADDICTION / DEPENDENCE: Methadone is highly addictive, and is one of the most difficult drugs to quit. See the Black Box warning below, and half life and metabolism.

SIDE EFFECTS: The wide range of methadone side effects include everything from body pain, agitation, and confusion to erectile dysfunction and infertility, and serious, life-threatening, or fatal respiratory depression and cardiac effects. See more info below.

WITHDRAWAL SYMPTOMS: Methadone withdrawal symptoms can be more severe and longer-lasting that those of other drugs. They include delusions, depression, rapid heartbeat, nausea, vomiting, and diarrhea. See more below.

TREATMENT: Medical detoxification. See more information below.



Methadone is a synthetic opioid prescribed as a painkiller or as the drug used in Medication Assisted Treatment (MAT) for opioid addiction. Methadone is intended to be used as just one element of MAT, along with a full drug detoxification or rehabilitation program that helps the addict get to the bottom of their addiction and what it will take to really overcome it so they can be truly rehabilitated – and not dependent on or addicted to any drugs (other than those that are truly medically necessary).

Methadone is not treatment in itself, it is simply used to help make withdrawal easier by helping to control some of the symptoms experienced while getting off other drugs, and reducing drug cravings while undergoing the actual treatment.

Methadone can be an extremely dangerous drug. Because of the nature of the drug, overdoses can occur easily, especially for someone just starting the drug or when the dose is increased.

Here is a description of the dangers of methadone, taken from the label.


Addiction, Abuse, and Misuse

Methadone hydrochloride tablets exposes patients and other users to the risks of opioid addiction, abuse, and misuse, which can lead to overdose and death. Assess each patient’s risk prior to prescribing methadone hydrochloride tablets, and monitor all patients regularly for the development of these behaviors or conditions.

Life-threatening Respiratory Depression

Serious, life-threatening, or fatal respiratory depression may occur with use of methadone hydrochloride tablets. Monitor for respiratory depression, especially during initiation of methadone hydrochloride tablets or following a dose increase.

Accidental Ingestion

Accidental ingestion of even one dose of methadone hydrochloride tablets, especially by children, can result in a fatal overdose of methadone.

Life-threatening QT Prolongation

QT interval prolongation and serious arrhythmia (torsades de pointes) have occurred during treatment with methadone. Most cases involve patients being treated for pain with large, multiple daily doses of methadone, although cases have been reported in patients receiving doses commonly used for maintenance treatment of opioid addiction. Closely monitor patients for changes in cardiac rhythm during initiation and titration of methadone hydrochloride tablets.

Neonatal Opioid Withdrawal Syndrome

Prolonged use of methadone hydrochloride tablets during pregnancy can result in neonatal opioid withdrawal syndrome, which may be life-threatening if not recognized and treated, and requires management according to protocols developed by neonatology experts. If opioid use is required for a prolonged period in a pregnant woman, advise the patient of the risk of neonatal opioid withdrawal syndrome and ensure that appropriate treatment will be available.



Methadone is a Schedule II drug – the same class as morphine, phencyclidine (PCP), cocaine, hydrocodone, fentanyl, and methamphetamine – and has a very high potential for abuse.



The Black Box warnings on methadone labels make it very clear that it is easy to become dependent on methadone and it is highly addictive.

In fact, it is just as addictive as heroin, prescription opiate painkillers or other similar drugs an addict might use methadone to overcome.

The difference is primarily that methadone, if taken at the prescribed dose, does not usually cause the euphoric feeling you get with those other drugs, and the person can therefore function in life somewhat normally. Someone who’s taking methadone is not generally taking it to get high. They’re taking it to relieve pain, or to help them get off another drug.

Methadone helps keep withdrawal symptoms to a minimum and curbs drug cravings.

However, methadone when used to help someone get off other drugs like heroin and other opioids and opiates (opioids are synthetic opiates, like prescription painkiller drugs) – is only supposed to be used for a brief time. It is supposed to be just a part of an addiction treatment program. The rest of the program is rehabilitation – which includes helping people to heal physically after extended periods of the negative effects caused by taking the drugs, digging into why the person became addicted in the first place, helping to resolve those problems, teaching the life skills they need to change their life, and helping them get into an environment and lifestyle that will not tempt them to get back into drugs.

There is generally no need for a person to stay on methadone for that entire treatment period – which could take many months. If they are kept on methadone for a long time, they’re going to become physically dependent on methadone instead of heroin or whatever they were taking before.

Getting off methadone is often more difficult than it would have been to simply have gotten off heroin in the first place.

Other than staying on methadone too long – some people are on it for years – the lack of treatment can also be a problem.

Even though it is mandated that anyone put on methadone to help them get off another drug is also to receive addiction counseling, many people don’t receive it. And those who do receive addiction counseling sometimes get to speak to a counselor only once a week or, if they aren’t covered by insurance, once a month. Thus someone can stay on methadone for years.


The biological half-life of a substance is the time it takes for a drug to lose half of its pharmacologic activity.  This is significant because it affects how soon withdrawal symptoms may appear.

The half life of methadone is longer than other drugs, including other opiates. Depending on the individual, it can be as long as 59 hours.

However, the effects of methadone don’t last anywhere near that time. For pain relief, for example, the effects are likely to last 4 to 8 hours.

The problem with this is that once the effects of methadone wear off, the person taking it has the impression that the drug is no longer in their system and, consequently, they take more.

When you combine the new dose with what’s still in the body from the last dose, you are at serious risk of overdose. In fact, this is one of the major factors contributing to overdose and deaths associated with methadone.

Also, according to the methadone label:

“A high degree of opioid tolerance does not eliminate the possibility of methadone overdose, iatrogenic or otherwise. Deaths have been reported during conversion to methadone from chronic, high-dose treatment with other opioid agonists and during initiation of methadone treatment of addiction in subjects previously abusing high doses of other agonists.”

“With repeated dosing, methadone is retained in the liver and then slowly released, prolonging the duration of potential toxicity.”

Methadone metabolizes via hepatic N-demethylation by cytochrome P450 (CYP) isoforms, principally CYP3A4, CYP2B6, CYP2C19, and to a lesser extent by CYP2C9 and CYP2D6.

The CYP enzymes are the major enzymes involved in drug metabolism, and since many drugs may increase or decrease the activity of various CYP isozymes, this is a major source of adverse drug interactions, since changes in CYP enzyme activity may affect the metabolism and clearance of various drugs. For example, if one drug inhibits the CYP-mediated metabolism of another drug, the second drug may accumulate within the body to toxic levels, possibly causing an overdose.

Combining methadone with drugs that might interfere with normal CYP activity – and there are many – can result in increased methadone concentrations in plasma – which can result in serious respiratory depression and could lead to overdose or death – or a decrease in concentrations, which can cause the methadone to be ineffective and, possibly, cause the development of withdrawal symptoms.



The side effects of methadone are many:

  • agitation
  • body pain
  • confusion
  • constipation
  • craving for sweets
  • dark urine
  • decreased or lack of sexual desire
  • diarrhea
  • difficulty breathing
  • difficulty swallowing
  • difficulty urinating
  • difficulty falling asleep or staying asleep
  • dizziness
  • dry mouth
  • erectile dysfunction
  • extreme drowsiness
  • falling asleep late
  • fast heartbeat
  • fever
  • flushing
  • frequent awaking
  • frequent urination
  • gas
  • get tired easily
  • hallucinations
  • headache
  • hives
  • hoarseness
  • inability to get or keep an erection
  • infertility
  • irregular menstruation
  • itching
  • jerky movements
  • lack of sleep
  • loss of appetite
  • loss of coordination
  • low vitamin B1, B2, C, iron, niacin, and minerals such as calcium, magnesium and zinc
  • mood changes
  • nausea
  • nightmares
  • orgasmic dysfunction
  • premature ejaculation impotence
  • rash
  • severe muscle stiffness
  • severe muscle twitching
  • seizures
  • shivering
  • sore tongue
  • stomach pain
  • sweating
  • swelling of the eyes, face, mouth, tongue, or throat
  • swollen body
  • swollen stomach
  • tiredness
  • urinary retention



The symptoms of methadone withdrawal can be more severe than those of any other drugs.

Before methadone was as widely used as it is now, people on online forums defended methadone, saying that without it, they couldn’t live a normal life. This is understandable when people have lived with chronic pain for years and have not been able to find or address the source of the problem successfully and can’t function well in life or are living a life of severe pain, with all of the emotion connected to that.

But many of those people were using methadone to stop taking heroin or other drugs. Using methadone, they were no longer ‘high’, and could function better – they could work, go to school, have a family life, and so on. Which was much better than being a heroin addict.

However, as the use of methadone ‘replacement therapy” and MAT (medication assisted treatment) have increased, so has the number of people being put on methadone.  But some are staying on it for years or decades. And more and more people are realizing how dependent they are and expressing how difficult it is to stop taking it and how much they want to quit, but can’t.

They didn’t start methadone because they wanted to get high. They wanted to get off drugs. Then they find themselves dependent on methadone and can’t get off it.

At first, it’s a relief to be able to function, not have to get access to heroin or opiates or wondering where their next dose is going to come from. Their life is no longer centered around drugs.

However, many people find that going to a methadone clinic every day gets old pretty quickly, and the longer they take the drug the more obvious it becomes to them that, although life is better, they’re still dependent on a drug. And that’s not what they signed up for.

One of the reasons it is so difficult to get off methadone is the severe withdrawal symptoms. Acute withdrawal symptoms can include:

  • aches and increased pain
  • acute sensitivity to pain
  • adrenal exhaustion
  • agitation and irritability
  • anxiety
  • visual and auditory hallucinations
  • chills
  • delirium
  • delusions
  • depression
  • diarrhea
  • fever
  • frequent yawning
  • goose bumps
  • increased perception of odors, real or imagined
  • decrease in sex drive
  • nausea
  • panic
  • paranoia
  • prolonged insomnia
  • rapid heartbeat
  • stomach cramps
  • sweating
  • thoughts of suicide
  • tremors
  • vomiting
  • watery eyes and runny nose

Without professional withdrawal help, some of these symptoms could go on for months.

Even after getting off methadone, former users can expect depression, anxiety, sleep problems, irritability, poor focus and concentration, and impaired decision-making skills to last for a long time.


With methadone withdrawal symptoms as severe as they are, and with so many people unable to stop taking methadone, even when they’re trying to taper down, getting professional, medically-supervised detoxification is vital.

A good medical detoxification program will help you get through withdrawal with the least amount of discomfort and painful emotion, while replenishing your body with the vitamins, amino acids and minerals you are deficient in, ensuring you get nourishing food and other physical help needed.

Different people experience different symptoms and with some people those symptoms are worse than others. A good detox program is not ‘one size fits all’. Instead, you should get the individual treatment you need based on what you, personally, are going through.