What Are the Side Effects of Methadone?

In the sphere of drug addiction treatment, methadone (brand names: Dolophine and Methadose) is an opioid medication that is used as a safe replacement for opioids in individuals who have a history of abusing these types of drugs. The history of methadone reveals that it was first used in 1964 in New York City to treat individuals who were addicted to heroin.

Methadone is available in the following formats: powder, tablets, and liquid (for the treatment of opioid abuse). In the addiction field, methadone is classified as a medication-assisted treatment (MAT). As the National Institute on Drug Abuse explains, replacing methadone for an opioid of abuse is considered a substitution therapy and does not support the creation of a new addiction. When a person takes methadone in accordance with an addiction treatment program, this is a sign of recovery. Since methadone is the oldest and most established form of MAT, it is helpful to know the side effects associated with it.

Methadone Side Effects

When a doctor initiates a person into methadone treatment, the goal is that the transition is smooth and results in the least number of side effects. If a person takes the advised dose, in the recommended timeframe, side effects should be minimal. However, due to varying physiological factors, some individuals may experience some side effects as a result of taking methadone.

The following are some of the most common methadone side effects:

  • Constipation
  • Mood changes
  • Sweating
  • Flushing
  • Sore tongue
  • Weakness
  • Headache
  • Nausea
  • Vomiting
  • Weight gain
  • Loss of appetite
  • Stomach pain
  • Dry mouth
  • Problems with vision
  • Trouble with urination
  • A lack of sexual desire or ability
  • In females, missed menstrual cycles
  • Problems falling asleep or staying asleep

Some individuals will experience serious side effects when taking methadone. It is critical to be apprised of what to look out for, which includes but is not limited to:

  • Seizures
  • Pounding heartbeat
  • Fainting
  • Hallucinations
  • Swelling of the eyes
  • Swelling of the face
  • Swelling of the mouth
  • Swelling of the tongue
  • Swelling of the throat
  • Hoarseness
  • Rash
  • Itching
  • Hives
  • Severe nervousness
  • Severe restlessness
  • Trouble breathing
  • Trouble swallowing
  • Extreme drowsiness

Methadone addiction can also be a side effect of methadone use, but only if a person abuses this substitution therapy. Since methadone is a narcotic treatment, individuals who take this drug will become physically dependent on it over time. Physical dependence is not addiction. Individuals who become addicted to methadone, through misuse, will develop a psychological attachment to this drug. As a result, there will be changes in their behavior, such as spending an inordinate amount of time getting, using, or recovering from methadone.

It is possible to overdose on methadone. If methadone reaches a toxic level in a person’s blood, side effects include a decrease in blood pressure and heart rate, severe depression of the respiratory system, and coma. A methadone overdose can be fatal. Individuals who take methadone in accordance with a doctor’s orders are unlikely to experience an overdose. Methadone can have significant merit as a treatment for opioid addiction, but it a narcotic and can present a considerable risk to one’s health and safety if abused.

It is one thing to be aware of possible methadone side effects; it is another to understand the neurobiological basis of the side effects. Methadone in the brain acts similarly to heroin. Methadone binds to the same receptors in the brain to which heroin (metabolized back to morphine) attaches. One difference is that methadone is stored in the body and released over time at a slower pace compared to heroin. Since methadone has a less intense impact on the brain receptors, but occupies the brain receptors, it can help a person to avoid experiencing withdrawal from heroin or another opioid. When a person is in withdrawal from opioids, cravings often emerge. Methadone can significantly reduce or eliminate these cravings. This is a critical function as drug cravings can trigger relapse. In short, methadone maintenance can help to prevent relapse.

Methadone can be used as a long-term treatment. If a person, in working with an addiction specialist, decides to end methadone treatment, a tapering approach will have to be initiated. A person must be tapered off methadone in order to avoid any uncomfortable side effects, known as methadonewithdrawal (since physical dependence is a side effect of methadone). In view of how methadone resembles an opioid in the brain, it is understandable that a host of side effects can emerge, depending on a person’s specific neurobiology. The brain operates as a delicate system of checks and balances, so even though methadone can stop or lessen withdrawal symptoms, it can also, for instance, interfere with a person’s respiratory system. Overall, methadone is considered a safe drug replacement therapy.

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