Effects of Methadone on the Brain and Body

2 min read · 2 sections

Methadone is an opiate medication that is most commonly used as a withdrawal management and opioid replacement medication for individuals who have developed opiate use disorders, particularly as result of heroin abuse.

 Effects of Methadone on the Brain and Body

All of the substances classified as opiates are derivatives of substances in the poppy plant, and the majority of these substances were developed as pain-relieving or pain control medications. Methadone can also be used as a pain-relieving drug.

Individuals who use methadone will experience very few effects associated with other opioid drugs, as methadone blocks the effects of these drugs. Methadone remains in the system longer than other opioid drugs like heroin and does not have the same intensity of psychoactive effects that many other opiate drugs produce. Nonetheless, the use of methadone is associated with feelings of mild euphoria and relaxation, and it can be a drug of abuse.

The DEA classifies methadone as a Schedule II controlled substance, signifying that it is useful for treating a number of medical conditions, but it also has a significant potential to be abused and to result in the development of physical and psychological dependence.

The Effects of Taking Methadone

According to the National Institute on Drug Abuse (NIDA), the DEA, and scholarly sources, such as the book Mechanisms and Treatment: Opioid Dependence, methadone use produces the following:


Short-term effects



  • Sedation, euphoria, drowsiness, pain relief, and feelings of relaxation
  • Side effects that include pinpoint pupils, nausea, constipation, decreased respiratory rate, decreased heart rate, sweating, and mood swings (anxiety or depression)
  • Effects associated with taking too much or an overdose that can include a decrease in blood pressure, decreased heart rate, significantly reduced breathing or shallow breathing, twitching or tremors, itchy skin, diarrhea, vomiting, cyanosis (a bluish tint to the lips and/or fingernails), extreme lethargy, confusion, and potential comatose state
  • Potential for death due to overdose



Long-term effects (mostly as a result of abuse)



  • Cardiovascular issues, often as a result of injecting methadone and potentially leading to collapsed veins, arteriosclerosis, etc.
  • Respiratory issues as a result of chronically reduced respiration rates
  • Menstrual cycle changes in women or sexual dysfunction in men
  • Issues with judgment, a tendency to engage in risky behaviors, and a lack of attention to personal hygiene
  • Changes in the brain that are associated with learning and memory, particularly learning by reinforcement in the area of the brain often referred to as the pleasure or reward center
  • The development of physical dependence
  • The development of an opiate use disorder

Methadone Addiction

Methadone Addiction

Individuals who use methadone without medical supervision or contrary to its prescribed uses may develop a substance use disorder – in this case an opiate use disorder or methadone addiction. This is a severe psychiatric disorder that has a number of negative ramifications associated with it.

In terms of its physical effects, individuals who abuse opiate drugs are often subject to neglect hygiene, self-care, and other habits that can result in a number of damaging issues. For instance, sharing needles to inject methadone significantly increases the probability of acquiring a blood-borne disease, such as HIV or hepatitis.

Individuals with opiate use disorders who combine drugs of abuse leave themselves open to potential physical issues that can lead to damage to organ systems and result in long-term health issues. These may include issues with hypertension, liver damage, damage to the cardiovascular system, and significant brain damage. Other issues, such as deterioration of dentition, issues with skin, etc., can also occur as a result of severe self-neglect, poor diet, or other habits that are detrimental to overall health.

Individuals who are placed on methadone as a withdrawal management strategy for heroin may be placed on a tapering program where the supervising physician will establish an initial dose of methadone and then periodically taper the dose down at specific intervals to wean the individual off methadone. This approach is designed to relieve the withdrawal symptoms associated with heroin or other opiates, as the individual develops a recovery program; however, the approach with methadone often continues on a long-term basis.

The American Society of Addiction Medicine reports that a long-term methadone maintenance program is often the result of individuals in these programs having numerous relapses and chronic issues with substance abuse. The methadone replacement program may continue indefinitely in the hopes that individuals who are getting methadone on a regular basis will not become involved in criminal activities and spread diseases associated with needle sharing and prostitution – ultimately, that they will be better able to lead relatively normal lives. Research on the effect of these long-term methadone maintenance programs is somewhat mixed. There are a number of objections to this type of intervention, all basically claiming that these programs simply replace one addiction with another addiction.

Individuals who use methadone for medicinal reasons or who abuse methadone are likely to develop physical dependence on the drug. Physical dependence consists of tolerance (the need to use more of a drug to achieve the desired effects) and withdrawal (the appearance of a number of negative physical and emotional symptoms when an individual abruptly discontinues use of the drug or abruptly cuts down the dosage). When an individual develops physical dependence on any substance as a result of medical treatment, it is not generally considered to be a symptom of a substance use disorder; however, when an individual uses a substance for nonmedicinal reasons and develops physical dependence on it, the symptoms of both tolerance and withdrawal are considered to be signs that the individual has developed a substance use disorder. The development of tolerance and withdrawal represent the interplay of both physical and emotional or psychological factors.

Finally, it should be mentioned that methadone is only legally distributed through facilities that offer these tapering or methadone maintenance programs. Methadone can only be legally obtained with a prescription, and its distribution is tightly controlled. Individuals should not attempt to obtain methadone illegally in an attempt to initiate their own tapering program, as there are a number of potential dangers associated with attempts to do this without medical supervision.

Need more info?
American Addiction Centers Photo
Take the first step towards recovery.
American Addiction Centers Photo
Make the process simple. Ensure your benefits cover treatment.
American Addiction Centers Photo
Explore American Addiction Centers locations nationwide.
View Our Treatment Centers