Medically Reviewed

Short and Long-Term Effects of Methadone Treatment

4 min read · 6 sections
What is methadone, and what does methadone do to your body? Are there short term effects of methadone, and is methadone bad for you? Explore the answer to these questions and more via this primer on methadone side effects. Also discover why methadone has been used as an effective treatment for opioid use disorder for more than 50 years.1
What you will learn:
How does methadone help to alleviate opioid withdrawal symptoms and treat opioid use disorders?
What are the side effects of methadone?
What levels of care are available for opioid use disorders?

What is Methadone? 

Methadone is a long-acting opioid agonist that’s regularly used as a maintenance treatment for opioid use disorders (OUDs) and as an opioid withdrawal medication.1,2 Like other opioids, methadone works by activating opioid receptors in the brain. But due to its more gradual impact on these receptors, methadone effects typically don’t include the same euphoria associated with other opioids.3 Proper use of methadone can also blunt the effects of illicit opioids, reduce opioid cravings and withdrawal, and assist those with an opioid use disorder in achieving and sustaining recovery.1,2 

While various generic forms of methadone are available, Methadose is a common brand name for the substance.4 Methadone is a schedule II controlled substance and its therapeutic use is tightly regulated. For use in treating opioid use disorders, methadone is only dispensed via special programs certified by the Substance Abuse and Mental Health Services Administration (SAMHSA).2 

Benefits of Methadone as a Treatment Drug

The most studied opioid use disorder medication available today, methadone can help people stop or decrease illicit opioid use and improve their health and functioning. Studies also show that methadone can minimize the risk of opioid overdose death and retain people in treatment better than treatment with a placebo or no medication.1 

In addition, methadone can not only minimize cravings and withdrawal symptoms but also act as a maintenance treatment to help people function more normally and maintain responsibilities related to school, work, families, and more. In effect, the substance can help people to participate in other forms of treatment and recovery support, which in turn can help them better cope with their OUD and maintain long-term recovery.5

Side Effects of Methadone 

Almost all medications have possible side effects. Methadone side effects include:2

  • Nausea, vomiting.
  • Slowed breathing.
  • Restlessness. 
  • Itchy skin.
  • Heavy sweating.
  • Constipation.
  • Sexual dysfunction.

A handful of more severe methadone side effects on the body include:2

  • Difficult or shallow breathing.
  • Lightheadedness.
  • Chest pain, fast or pounding heartbeat. 
  • Hallucinations or confusion.

Long Term Side Effects

How long can you be on methadone, and are there long term effects of methadone? 

Under medical supervision and when taken as prescribed for the treatment of OUD, methadone is safe to use as long as it’s beneficial, be it for months, years, or indefinitely.6 In fact, SAMHSA guidance indicates that OUD medication can be continued in stable patients for as long as it is beneficial to them.1

Due to its pharmacological effects, methadone has the potential for certain health effects, even when used therapeutically. Certain risks involve respiratory, cardiovascular, and gastrointestinal issues. Special care is taken with individuals at particular risk for issues such as these, and your prescribing physician will monitor your treatment progress closely and make appropriate adjustments to your therapeutic regimen as needed.7

Methadone Risks

As noted above, methadone can be safely used in the long-term as an OUD treatment medication. However, the substance must be taken as prescribed and under a physician’s guidance, as methadone use—like most pharmaceuticals—involves additional risks including:1,2,6,8

  • Overdose. Due to methadone’s long-acting nature, its potential for overdose may increase when it is not used as directed (i.e., when it is used in higher than recommended doses and/or dosed more frequently than it should be). 
  • Neonatal abstinence syndrome (NAS). Infants whose mothers were treated with methadone during pregnancy are at risk of developing NAS. That said, methadone has been shown to improve birth outcomes among pregnant women with opioid use disorders. That’s because withdrawal during pregnancy is linked to a risk of premature birth and miscarriage. And since methadone can prevent withdrawal symptoms, it can assist pregnant women in better managing their OUD while limiting risks to the mother and baby. Bottom line: Methadone is safe for pregnant and breastfeeding women, but it’s important for them to work with their healthcare providers to best manage any symptoms of NAS in their infants. 
  • Respiratory depression. Similar to some other opioids, a risk of respiratory depression is associated with methadone use, though the greatest risk occurs at the initiation of therapy or following a dosage increase. In addition, mixing opioids such as methadone with benzodiazepines and other central nervous system depressants—including alcohol—can result in profound sedation, respiratory depression, coma, and death. 
  • Accidental ingestion. Particularly when it comes to children, accidental ingestion of methadone can result in an overdose.
  • Irregular heartbeats. Arrhythmias in association with changes in cardiac electrical conduction (known as QT interval prolongation) have been observed with methadone use. However, these conditions are more commonly associated with patients treated for pain with large, multiple daily doses of methadone. 

It’s important to note that methadone affects those not dependent on opioids differently. For these individuals, methadone can produce euphoria, and as a schedule II drug, methadone has a potential for dependence and addiction.5,9 

That said, methadone misuse and diversion (i.e., the illicit redistribution of prescription drugs that transfers them from their intended recipients to unauthorized users) is typically associated with methadone prescribed for the treatment of pain—not for OUD treatment. Plus, data illustrates that methadone diversion usually isn’t driven by a desire to get high. Rather, it’s more likely associated with a lack of access to medication for OUD treatment. Thus, in most cases, those that obtain methadone from an unauthorized source do so to control their cravings and withdrawal symptoms. Additionally, most instances of methadone diversion and overdose deaths are associated with methadone that has been prescribed for the treatment of pain.10 

Symptoms of Overdose

Used as prescribed, methadone can be safe and effective for treating opioid use disorder. But given the substance’s long-acting nature, when used more frequently or in higher than prescribed doses, the risk of overdose is increased.2 

Opioid overdose symptoms can include:11

  • Small, constricted, pinpoint pupils.
  • Falling asleep or loss of consciousness.
  • Respiratory depression, or slow, shallow breathing.
  • Pale, blue, or cold skin.

If you suspect that you or someone else is overdosing, the Centers for Disease Control and Prevention (CDC) offers this guidance:11 

  • Call 911 right away.
  • Give the person naloxone*, if available.
  • Keep the person awake and breathing.
  • Lay the person on their side to prevent choking.
  • Stay with them until emergency help arrives.

*Naloxone—which is available via brands such as Narcan, Kloxxado, and RiVive—is a life-saving medication that can rapidly reverse the effects of opioid overdose and restore a person’s breathing. However, naloxone must be administered quickly, and its effects are temporary. Thus, it’s important to seek immediate medical attention even after naloxone is given. 12

Rehab for Opioid Addiction

As previously noted, methadone diversion is most often associated with methadone used to manage pain—not for OUD treatment.10 Within this misuse framework, rehab for opioid addiction is customized to the unique needs of each individual. However, common levels of care include:13,14 15

  • Detox. If methadone misuse has led to physiological dependence or if an individual wants to stop using methadone as a treatment drug, it’s important to seek medical advice to slowly reduce the dose rather than abruptly stopping use. Medically supervised detox ensures patients are as safe and as comfortable as possible during the withdrawal process.
  • Inpatient treatment. Comprising highly structured days and 24/7 care and monitoring, inpatient care includes therapy, supervision, counseling, psychoeducation, and more. Patients live in a rehab facility surrounded by caring professionals as well as peers.
  • Outpatient treatment. Outpatient programs vary in intensity and include traditional outpatient rehab as well as partial hospitalization programs (PHPs) (aka day treatment and high intensity outpatient programs), intensive outpatient programs (IOPs), and telehealth services.
  • Aftercare programs. To promote patient success following inpatient and/or outpatient rehab, aftercare programs include sober living facilities, ongoing therapy, 12-Step programs, and more. 

If you or someone you love is struggling with addiction, American Addiction Centers can help.  Offering several levels of care that incorporate evidence-based treatment in a variety of U.S. locations, AAC treats a host of substance use disorders including those involving opioids. Admissions navigators at can assist you in making decisions about methadone treatment as part of detox and/or ongoing opioid use disorder treatment.

Take the first step toward recovery today by speaking with an admissions navigator or by verifying your insurance benefits online. Available 24/7 for a free and confidential conversation, AAC staff can discuss payment options and treatment particulars. And if you don’t feel like talking, text options are also available. 

Reach out now to take your first step toward a lasting recovery.

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