Methadone Side Effects, Usage, Detox & Withdrawal Symptoms

methadone side effects
Amanda Stevens

Written By

Amanda Stevens
Dr. Po-Chang Hsu -

Medically Reviewed By:

Dr. Po-Chang Hsu

Last Medically Reviewed on February 23, 2024


  • Methadone treats pain and addiction, but has side effects and misuse risks.
  • It eases withdrawal and cravings, as liquid or pill.
  • Side effects include heart-related problems and dependence.
  • Long-term use leads to tolerance, cognitive effects, interactions, and risks.

Methadone was first synthesized in the 1930s and was later introduced during World War II as a painkiller. Methadone began to be used as a treatment for heroin addiction in the 1960s, particularly gaining prominence after the opening of the first methadone maintenance clinic in 1964. Since then, Methadone has been used to help people overcome their opiate dependence in both short-term and long-term programs.

However, much like any controlled drug, there are risks associated with taking Methadone in the form of mild to severe side effects, as well as the potential for misuse and abuse. It is important to thoroughly understand these risks before beginning treatment and to know how to identify common withdrawal signs and symptoms.

What Is Methadone?

Methadone[1] is classified as a synthetic opioid – which means it is a man-made substance that acts in a similar way to natural opiates like morphine and heroin. However, it does not exactly mirror their chemical structure. The drug was designed as an effective alternative for individuals struggling to manage their opioid dependence.

Similar to the way heroin affects the pain receptors in the brain, Methadone is designed to help an individual relieve the pain associated with addiction withdrawal as well as reduce cravings. Methadone can be administered in the form of a tablet or liquid, and its effects can last up to 24 hours.

What Does Methadone Look Like?

While the appearance of Methadone can vary slightly depending on the manufacturer or the strength of the drug, there are typically two different ways it is administered – as an oral liquid solution or in a pill form.

As a liquid, Methadone is administered orally and usually comes in a red, cherry-flavored liquid or can also be clear and unflavored. In its pill format, Methadone will look like a white and round tablet with a score line in the middle to make it easier to break apart in smaller doses.
Methadone Side Effects

Methadone, a synthetic opioid, is categorized as a Schedule II drug under the Controlled Substance Act, and it’s only lawful to be administered by qualified medical personnel. This is because individuals using Methadone are at risk of experiencing a wide range of adverse effects, some of which may be severe and frequent.

Among some of the effects associated with methadone use, there are adverse effects[2] that can affect the heart and overall health of the body. These effects, in addition to the typical side effects that methadone users may encounter, include:

  • Nausea or Vomiting
  • Mood Changes
  • Chest Pain
  • Change in Heart Rate
  • Dry Mouth
  • Drowsiness
  • Sexual Dysfunction
  • Dizziness or Lightheadedness
  • Vision Problems
  • Sleep Changes
  • Weight Gain
  • Rash or Itchy Skin
  • Changes In Appetite
  • Stomach Pains
  • Constipation
  • Heavy Perspiration

Withdrawal Symptoms From Methadone

Since Methadone, by design, is intended to be a more suitable replacement for heroin or other opioids, it does contain addictive properties that can lead to certain withdrawal symptoms when weaning off of the drug.

While the withdrawal symptoms of Methadone may not be as severe or as long-lasting as those suffering from other opioid addictions, primarily due to its controlled administration, certain withdrawal symptoms can occur, including:

  • Muscle Aches and Pains
  • Sweating
  • Nausea
  • Anxiety
  • Agitation
  • Dilated Pupils
  • Increased Heart Rate and Blood Pressure
  • Hallucinations
  • Seizures

Methadone Overdose Symptoms

Accidental or intentional misuse of Methadone can be potentially fatal, and it’s vital to watch for any signs of an overdose. Symptoms of a methadone overdose[3] include:

  • Difficulty Breathing
  • Physical Weakness or Dizziness
  • Cold, Clammy Skin
  • Slow or Irregular Heartbeat
  • Low Blood Pressure (Hypotension)
  • Seizures
  • Loss of Consciousness
  • Blue or Purple Lips and Fingernails

It’s vital if you or someone else experiences any of these symptoms while taking Methadone, seek help. Get emergency medical treatment right away and call 911 immediately.

Methadone Side Effects, Usage, Detox & Withdrawal Symptoms

Long-Term Effects Of Methadone

Long-term use of Methadone can have certain physical effects on the body that, if left unchecked, can lead to potentially dangerous health complications. Some of the most common physical side effects associated with long-term methadone use include:

  • Physical Dependence – As the body continues to adapt to regular methadone consumption, it may begin to require it to function normally.
  • Increased Tolerance – Over time, the body may become too tolerant of Methadone, requiring higher doses of the medication to experience the same effects.
  • Cognitive Effects – Long-term Methadone use can lead to cognitive regression, including impaired attention, memory, or decision-making abilities.
  • Respiratory Depression – If taken for too long, Methadone can lead to slower and shallower breathing, which can be dangerous at high doses.

Long-Term Side Effects Of Methadone

While many of the side effects associated with Methadone use are typically short-term, there are some potential long-term side effects. These may include tolerance and physical dependence, confusion, depression, increased risk of overdose, and an increased risk of developing other mental health issues.

Additionally, Methadone can interact with certain medications or supplements and may cause a dangerous reaction when combined. It is important to always speak with a qualified doctor or pharmacist about any potential drug interactions before taking Methadone.

Liquid Methadone Side Effects

Liquid Methadone is designed to be taken orally and, therefore, has many of the same side effects as other formulations of Methadone. These may include nausea, drowsiness, dizziness, dry mouth, weight gain, and rash or itchy skin. Like other formulations of methadone, liquid Methadone may cause digestive problems such as constipation, upset stomach, or abdominal pain.

Recover With Hope And Pursue Healing At Recovery Unplugged

Methadone has many benefits for individuals suffering from physical pain and opioid addiction. However, it is important to remember that the side effects can contribute to other addictive behaviors if not managed properly.

At Recovery Unplugged, we offer a comprehensive approach to recovery and drug addiction treatment that helps our clients break the dangerous cycle of methadone dependence. If you or someone you know needs help finding long-term sobriety and healing, contact us today and let us help.

What Are The Risks of Combining Methadone And Alcohol?

Combining the use of Methadone and alcohol is very dangerous. Both Methadone and alcohol contain sedative effects that can cause drowsiness, impaired coordination, and slower breathing. Combining both substances can lead to heart failure, coma, and even death.

What Are The Common Symptoms of Detoxing From Methadone?

As the body becomes used to the presence of Methadone, once it starts to go without it, there can be adverse effects that can last anywhere between a few days to a few weeks. During detoxification, these symptoms can include nausea, diarrhea, insomnia and sleep disturbance, irritability, headaches, cravings, depression, and heavy sweating and chills.

How Effective Is Methadone For Pain Management?

Yes. Methadone binds to the same opioid receptors in the brain as other opioids but has a unique pharmacological profile that includes a longer duration of action and different side effect profiles. However, since it isn’t administered the same way as heroin, it is generally safer to avoid the danger of contracting HIV or other serious infections from shared needles. Methadone has a long duration of action, meaning that one dose is usually effective for pain relief for up to 24 hours.

Are There Any Dangers Associated With Methadone And Pregnancy?

Opioids like methadone can be associated with risks during pregnancy, but methadone maintenance therapy is often considered safer for pregnant women with opioid dependence than continuing illicit opioid use.


However, there are certain medication-assisted treatment (MAT) programs that can be used to safely administer Methadone during pregnancy by medically supervised professionals. However, pregnant women should seek advice from their doctor before starting any MAT program, as there are increased risks associated with birth defects, premature labor, and other complications.

Is Liquid Methadone Different Than Pill Form?

Liquid methadone and pill form have the same active ingredient, but the liquid form may allow for more precise dosing adjustments. The absorption rate and potency are generally similar, although individual responses can vary.

What Are The Benefits And Drawbacks Of Using Methadone For Pain Management?

Methadone has been proven to help with long-lasting pain relief while helping individuals avoid the dangers of using drugs like heroin to achieve similar effects. It is also more affordable than other opioids, such as oxycodone or hydrocodone, and can be taken orally instead of needing to be injected. However, its addictive properties and potential for abuse mean that it should only be used with extreme caution and under the close guidance of a qualified doctor.

We take our music-focused treatment for addiction very seriously, so we are going to hold our content to the same precision standards. Recovery Unplugged’s editorial process involves our editing safeguard and our ideals. Read our Editorial Process.


[1] SAMHSA. (2024, February 5). Methadone.

[2] Durrani, M., & Bansal, K. (2024). Methadone. In StatPearls. StatPearls Publishing.

[3] Mount Sinai Health System. (2024). Methadone overdose Information | Mount Sinai—New York. Mount Sinai Health System.

Amanda Stevens

Amanda is a prolific medical content writer specializing in eating disorders and addiction treatment. She graduated Magna Cum Laude from Purdue University with a B.S. in Social Work.

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