Many people take methadone in order to treat opioid addiction, but this medication can still create risks like dependence, addiction and overdose.

Methadone is a medication commonly used in opioid addiction treatment. It can help reduce cravings, prevent withdrawal symptoms and help people maintain long-term recovery. However, because methadone is also an opioid, there are still certain risks involved with its use.

All opioids — even less potent ones like methadone — can lead to abuse, dependence, addiction and overdose. Before taking an opioid medication like methadone, it’s important to be aware of its potential side effects, risks and long-term impact.

Signs of Methadone Use

It can be difficult to tell when someone is using methadone, especially if they’re taking a recommended dose. This is primarily due to the drug’s 59-hour half-life, which is much longer than that of more potent opioids, such as heroin. This long half-life is also the reason why methadone does not create a powerful high.

A drug’s half-life refers to how long it takes for half of the drug to be cleared from the body. It normally takes five half-lives to completely clear a drug from the system. This means that most people will clear methadone from their systems 295 hours after the last dose.

Although it can be hard to see signs of methadone use when it’s taken as prescribed, they can still occur. These signs are more likely to appear when someone first begins methadone treatment, and they can vary depending on the person and the dose they take. Signs may include:

  • Nausea
  • Vomiting
  • Sweating
  • Constricted pupils
  • Slowed breathing
  • Constipation
  • Confusion
  • Drowsiness

Methadone Tolerance, Dependence and Addiction

In small doses, a person taking methadone may still be able to function normally in their day-to-day life. If they start taking higher doses in response to a growing methadone tolerance, however, this can change. They can start to seem sluggish or become unable to do things like driving a car or operating machinery.

Often, as a person begins to develop an opioid tolerance, they will become increasingly focused on trying to get more to achieve the same effects. They may attempt to get multiple prescriptions from different health care providers, and they may start taking higher doses. When it seems as if a person’s biggest priority involves obtaining and taking methadone — and they’re failing to meet work, family and social commitments — it’s often a sign of addiction.

If someone with methadone dependence or addiction stops taking the drug, they will likely experience withdrawal symptoms. These symptoms can include:

  • Yawning
  • Restlessness
  • Sweating
  • General achiness
  • Gastrointestinal issues
  • Vomiting
  • Cramps

Compared to other opioids, methadone withdrawal symptoms can take longer to appear (up to 48 hours). However, they may also last longer (up to 10 days).

Physical Symptoms of Methadone Use

The first time someone takes methadone, they may feel common physical side effects. These can include:

  • Weakness
  • Headache
  • Gastrointestinal problems (constipation, nausea, vomiting)
  • Weight gain
  • Loss of appetite
  • Sore tongue
  • Dry mouth
  • Flushing
  • Sweating
  • Vision problems
  • Problems urinating
  • Sexual problems
  • Missed menstrual periods
  • Sleep problems
  • Slower reflexes
  • Clamminess
  • Trouble concentrating
  • Weak muscles

Some physical symptoms, such as altered sense of perception, lightheadedness and sedation, are the reasons why people abuse methadone. While the high may not be as powerful as with other opioids, it can still lead to feelings that some may find appealing.

There can also be severe methadone side effects. Some of the more serious effects on the body can include:

  • Seizures
  • Itching, hives or rash
  • Rapid heartbeat
  • Nervousness
  • Restlessness
  • Swelling of the mouth, tongue and throat
  • Swelling of the face and eyes
  • Difficulty swallowing
  • Difficulty breathing
  • Severe drowsiness
  • Fainting
  • Hallucinations

Impact on Long-Term Health

For most people who take methadone as a way to recover from opioid addiction, the long-term health benefits outweigh the risk of possible side effects. For this reason, many people remain on methadone treatment indefinitely.

Methadone can help improve long-term physical and psychological health, especially in regard to:

  • Reducing risk of HIV/AIDS, hepatitis C and other bloodborne diseases
  • Improvement of family life and relationships
  • Improved employment prospects
  • Improved sleep
  • Improved appetite
  • Increased sexual desire

Can You Overdose on Methadone?

It is possible to overdose on methadone, either accidentally or intentionally. The amount necessary to overdose varies based on the individual and their level of opioid tolerance. A person can also overdose on methadone if they take it with other painkillers, such as oxycontin, morphine or hydrocodone.

Methadone doesn’t cause a powerful rush of euphoria like other drugs, but it is relatively inexpensive. People who are addicted to other drugs may unintentionally overdose on methadone while trying to achieve a high. Additionally, a person may not realize that methadone is extremely long-acting. As a result, they may take too much too quickly, causing the drug to build up in their system.

If you or someone you love is struggling with methadone use or an opioid addiction, The Recovery Village is here to help. Contact us today to learn more about treatment plans and rehab programs that can work well for your needs.

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Editor – Jonathan Strum
Jonathan Strum graduated from the University of Nebraska Omaha with a Bachelor's in Communication in 2017 and has been writing professionally ever since. Read more
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Medically Reviewed By – Dr. Jessica Pyhtila, PharmD
Dr. Jessica Pyhtila is a Clinical Pharmacy Specialist based in Baltimore, Maryland with practice sites in inpatient palliative care and outpatient primary care at the Department of Veteran Affairs. Read more

Hallare, Jericho; Gerriets, Valerie. “Half Life.” StatPearls, October 6, 2020. Accessed September 7, 2021.

World Health Organization. “Clinical Guidelines for Withdrawal Manag[…]e in Closed Settings.” 2009. Accessed September 7, 2021. “Methadone.” July 31, 2020. Accessed September 7, 2021.

National Institute on Drug Abuse. “Principles of Drug Addiction Treatment: A Research-Based Guide (Third Edition).” January 2018. Accessed September 7, 2021.

Kheradmand, Ali; Banazadeh, Nabi; Abedi, Heidarali. “Physical Effects of Methadone Maintenanc[…]tandpoint of Clients,” Addiction & Health, 2010. Accessed September 7, 2021.National Institute on Drug Abuse. “What is the treatment need versus the di[…] disorder treatment?” June 2018. Accessed September 7, 2021.

Medical Disclaimer

The Recovery Village aims to improve the quality of life for people struggling with substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare providers.