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Methadone Abuse Side Effects & Addiction Signs

Written by Jonathan Strum

& Medically Reviewed by Dr. Annie Tye, PhD

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Last Updated - 12/29/2022

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Updated 12/29/2022

Key Takeaways

  • Methadone misuse often causes a loss of interest in normal activities, irresponsible behavior, inability to concentrate and sudden mood swings
  • Physical effects of methadone misuse can include weight gain, dizziness, constipation, nausea/vomiting, itchy skin and dental problems
  • Psychological effects of methadone misuse can include anxiety, irritability, decreased sexual desire and lethargy
  • Methadone overdoses can cause respiratory depression, slow or rapid heart rate, coma and death
  • Methadone misuse has decreased as methadone prescriptions become more difficult to get, but accurate statistics are rare
  • Methadone treatment typically involves a period of detox and withdrawal, followed by residential and outpatient care
  • Many substance use disorders are associated with underlying mental health issues or past traumas. A dual diagnosis often identifies factors that contribute to substance misuse.
  • Methadone clinics typically provide methadone to people who struggle with heroin, fentanyl, oxycodone or morphine addiction. Methadone has similar effects as these drugs but does not lead to euphoria when taken as prescribed.
  • Methadone should only be used as directed and should never be given away

Learn about what methadone use disorder looks like and how to achieve recovery from methadone dependence or addiction.

Methadone is an opioid that is commonly prescribed to treat severe pain or help people who are experiencing opioid withdrawal symptoms. Methadone use disorder is associated with several physical and psychological side effects that can help identify someone who is struggling with methadone dependence. People can recognize addiction early and get help by understanding the signs and symptoms of methadone use, signs of overdose and options for treating methadone addiction.

How Is Methadone Abused?

Like all opioids, methadone use carries the risk of dependence or addiction. Many people who use methadone had legitimate opioid prescriptions at one point, but they were unable to stop using opioids when their prescription ran out. Methadone abuse can be done by ingesting pills or liquid solutions, injecting the drug, smoking or snorting.

There are legitimate long-term uses for methadone in some cases. While methadone can cause addiction, it is far less addictive than opioids like heroinfentanyloxycodone and morphine. When someone uses powerfully addictive opioids, substantial changes in brain chemistry occur rapidly. The effects can last for years and can be incredibly debilitating. Methadone has similar physical effects in the brain but lacks the euphoric high that is associated with other opioids.

For people who struggle with opioid addiction, methadone can replace the opioid they used in the past to get high. Methadone essentially tricks the brain into thinking that it has its drug of choice, but methadone doesn’t have the powerful reinforcing effects that the opioid high delivers. For people with a debilitating opioid addiction, methadone can offer a way to reintegrate into society, maintain gainful employment and develop healthy relationships.

In these cases, methadone maintenance treatment can be lifesaving. However, people must take it as prescribed and under the direct care of medical professionals.

Methadone Addiction Signs

Like most addiction disorders, people who struggle with methadone use disorder will likely experience behavioral changes, including:

  • Loss of interest in hobbies
  • Irresponsibility
  • Isolationism
  • Rapid mood swings
  • Inability to focus or complete tasks
  • Lethargy

Methadone Side Effects

When used as directed, methadone side effects are typically mild. However, high doses are associated with a sense of euphoria and sedation, especially in people who have not struggled with prior opioid dependency. Effects of methadone on the body are physical as well as mental.

Physical Effects

Some of the physical side effects of methadone are:

  • Weight gain: Most people who report weight gain after methadone are involved in methadone maintenance treatment programs. As they begin to make healthy lifestyle choices, their weight may go up. Evidence also suggests that opioid use (including methadone) is associated with increased sugar intake, which can lead to weight gain.
  • Constipation: Opioids, including methadone, can cause constipation. In fact, an opium derivative called laudanum was the earliest known treatment for diarrhea, dating back to the 15th century. While opioid receptors are most commonly associated with the brain, there is also an opioid receptor network in the gut. Methadone use affects gut contraction in two ways: direct action in the gut and indirect action through the brain. Both actions reduce gut contraction and lead to constipation. Opioids also cause increased fluid absorption in the gut, which causes stools to harden.
  • Tiredness: Tiredness and fatigue are non-specific symptoms that are reported by some methadone users. Opioids are central nervous system depressants (sedatives), so reduced energy levels are common, especially with high doses. Chronic methadone users or people in maintenance treatment programs are more likely to report daytime sleepiness that affects normal daily function. This could be due to an opioid-induced adrenal insufficiency, where hormone production is slowed. However, the precise relationship between methadone use and fatigue remains unclear.
  • Tooth problemsMethadone use is associated with poor oral health. There are likely multiple contributors to this, including dry mouth. A dry mouth can make teeth prone to plaque production, which promotes gum decay. Sugar-based liquid methadone formulations can also cause dental issues.

Mental Effects

One of the reasons why methadone is effective in treating opioid addiction and withdrawal is that it has few substantial psychological effects. It effectively tricks the brain into believing that powerful opioid narcotics like heroin or fentanyl have been ingested. With methadone, though, the user does not experience the euphoria that is associated with heroin and fentanyl. High doses of methadone, however, can cause mild euphoria in people who take it for pain management and do not have dependency.

Long-term effects of methadone on the brain are still being evaluated. Mounting evidence suggests that chronic methadone use can affect more than opioid receptors and reward centers in the body. The effects may depend on what methadone is being used to treat.

A study was done on people who used methadone maintenance therapy for heroin addiction. It found that cognitive performance increased over time, but the integrity of white matter in the brain decreased. However, people with methadone use disorder who originally took it for pain management have a much higher risk for negative outcomes on brain structure and function. In addition, methadone-induced brain changes are more profound in adolescents and young adults, whose brains are still developing. Young people in particular should never be prescribed methadone for long-term pain management.

Methadone Abuse Facts and Statistics

Methadone use is increasing in the U.S. The number of people in methadone maintenance treatment programs increased 37% between 2003–2015. Methadone misuse is substantially lower than misuse associated with other opioids that are prescribed for pain management. Statistics show that only 0.1% of people aged 12 or older misused methadone within the past year, compared to 4.3% for hydrocodone and 2.6% for oxycodone.

Methadone Abuse and Treatment Trends in South Florida

According to the National Early Drug Warning System, methadone-related deaths in South Florida declined by approximately 5% between 2011–2015. Of all deaths associated with opioids, only 2.8% were linked to methadone in 2016 (23 methadone-related deaths out of a total of 827 opioid-related deaths).

Seizures of illicit methadone are also rare. In 2016, methadone seizures by Miami law enforcement made up only 0.7% of opioid seizures and 0.1% of total drug seizures. This suggests that methadone misuse is declining in South Florida. However, it is important to note that reliable statistics for substance use disorders are difficult to obtain. Low rates of illicit methadone seizures do not necessarily reflect low levels of methadone misuse.

Methadone Overdose Symptoms

Methadone overdose is a medical emergency that can lead to death. Methadone is a central nervous system depressant that can lead to respiratory depression, low blood pressure, coma or death. Symptoms of methadone overdose include:

  • Nausea or vomiting
  • Dizziness
  • Disorientation
  • Profound lethargy
  • Confusion
  • Muscle twitching or weakness
  • Hypothermia

If you suspect a methadone overdose, call 911 immediately.

How to Get Off Methadone

Most medical professionals recommend tapering off of methadone. Like other opioids, methadone withdrawal is associated with uncomfortable side effects that can be somewhat reduced by tapering the dose.

The initial days or weeks after reducing or quitting methadone can be difficult. Many people have the most success by undergoing detox and withdrawal under the supervision of medical professionals at a detox facility. Staff members can address concerns and provide medication to help with withdrawal if necessary. Resources for people with methadone use disorder include:

  • Detoxing off methadone: The detox period can be uncomfortable. Withdrawal symptoms typically include nausea or vomiting, sweating, anxiety, irritability and lack of pleasure.
  • Methadone clinics: Methadone clinics provide daily doses of methadone to people who are in recovery from heroin or other opioid use disorders. A methadone clinic can be a valuable stepping stone for people who are in recovery.
  • Outpatient: Outpatient rehab is an important component of recovery. Some people with mild dependency issues may find that outpatient rehab is enough, but most people will enter an outpatient program after a period of residential care. Outpatient programs vary quite a bit, ranging from daily to weekly sessions. The goal of outpatient rehab is to give clients an opportunity to begin a sober lifestyle while maintaining a strong support network that can help clients avoid triggers and relapse.
  • Dual diagnosis: Underlying mental health issues are a component of substance use disorders. Many people use drugs to mask emotional issues or past trauma. A dual diagnosis can help clients understand if they are using substances as a way to avoid dealing with disorders such as anxiety, depression or PTSD.

See Related: Methadose vs Methadone

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