What are the Side Effects of Methadone?

Although carefully monitored dosages of methadone are legally and medically acceptable, methadone is still an opioid agonist drug like heroin. It’s important to recognize that, while methadone is a milder drug, it is still a narcotic with a high chance of addiction and dangerous methadone side effects. When an individual takes this medication in any form, they risk experiencing a host of hazardous consequences, which can cause both psychological and physical harm.

What is Methadone?

Methadone is a prescription drug used to treat severe pain. It is also a medication for detox and maintenance treatment of opioid addiction, such as heroin addiction. Methadone is itself an opioid and can be addictive. Some people can become addicted to methadone as they use it to wean themselves off of another prescription painkiller. Methadone detox and addiction treatment programs can help ensure a safe withdrawal process.

Methadone may be prescribed by physicians and dispensed by community pharmacies for analgesia as a Schedule II drug under the regulations of the Controlled Substances Act [1]. However, when used for the treatment of opiate dependence, methadone’s accessibility is restricted to practitioners, clinics, and pharmacies licensed by the Food and Drug Administration (FDA).

In 2017, about 261,000 people age 12 and older reported using methadone for a non-prescribed purpose at least once in their life [2]. Once the body relies on methadone to function normally, dependency on this drug will develop. In addition, those with methadone dependency will experience withdrawal symptoms if they quit taking the medication.

What Does Methadone Do?

Methadone works by changing how the nervous system and the brain respond to pain. It reduces the painful symptoms of opiate withdrawal. It blocks the euphoric effects of opiate drugs such as morphine, heroin, and codeine, as well as semi-synthetic opioids like hydrocodone and oxycodone.

Opioid-dependent individuals take a daily dose of methadone as a liquid or pill. Pain relief from a dose of methadone lasts about four to eight hours. Methadone is effective in higher doses, especially for heroin users, helping them stay in treatment programs longer.

As with medications used in medication-assisted treatment (MAT), methadone is usually prescribed as part of a comprehensive treatment plan for opioid and opiate addiction that includes therapy and participation in social support programs.

People with methadone prescriptions need to take it exactly as prescribed and not adjust their dose without a doctor’s advice and oversight. It is easy to overdose on methadone due to the strength of one dose. Methadone and Suboxone are both opioids. While methadone is used to treat chronic pain and opioid addiction, Suboxone is only approved to treat opioid addiction.

How is Methadone Used?

Methadone comes as a tablet, a dispersible (can be dissolved in liquid) tablet, a solution (liquid), and a concentrated solution to take by mouth. When methadone is used to relieve pain, it may be taken every 8 to 12 hours. If you take methadone as part of a treatment program, your doctor will prescribe the dosing schedule that is best for you. Follow the directions on your prescription label carefully and ask your doctor or pharmacist to explain any part you do not understand. Take methadone exactly as directed.

If you are using the dispersible tablets, do not chew or swallow before mixing the tablet in a liquid. If your doctor has told you to take only part of a tablet, break the tablet carefully along the lines that have been scored into it. Place the tablet or piece of the tablet in at least 120 mL (4 ounces) of water, orange juice, or a citrus fruit drink to dissolve. Drink the entire mixture right away. If some tablet residue remains in the cup after you drink the mixture, add a small amount of liquid to the cup and drink it all.

Methadone Side Effects

Along with its needed effects, methadone may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Methadone Side Effects Requiring Immediate Medical Attention

Check with your doctor immediately if any of the following side effects occur while taking methadone:

Get emergency help immediately if any of the following symptoms of overdose occur while taking methadone:

Symptoms of overdose

Methadone Side Effects Not Requiring Immediate Medical Attention

Some side effects of methadone may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Methadone Side Effects on Heart

Methadone may cause a life-threatening heart rhythm disorder. Call your doctor at once if you have a headache with chest pain and severe dizziness, and fast or pounding heartbeats. Your heart function may need to be checked during treatment. 

Methadone Side Effects on Stomach

Methadone can cause various side effects associated with upset stomachs such as diarrhea, vomiting, nausea, and abdominal pain. Many similar symptoms are associated with opiate withdrawal but while taking methadone, these symptoms are generally less severe and will subside on their own in time. If you experience any side effects that prevent you from holding down fluids for a prolonged period, you should seek prompt medical attention as this could lead to dehydration and other serious complications.

Methadone Side Effects on Skin

Feeling itchy after taking methadone isn’t usually a major cause for concern. This is common, and the sensation may subside shortly. A methadone allergy or adverse reaction to methadone, however, is worth discussing with your doctor. Together, you can both determine whether continuing to take methadone is right for you.

Methadone Side Effects on Teeth

Methadone side effects on teeth aren’t often as pronounced as what’s seen with methamphetamines, but it can contribute to some tooth decay. The reason methadone side effects on teeth are present is that it can cause dry mouth, which increases the presence of bacteria and plaque in the mouth.

Methadone Overdose

Methadone overdose happens when a person intentionally or accidentally takes more than the recommended or normal amount of this medicine. This can be on purpose or by accident. Make sure to let your doctors know about any medications you’re taking.

Even though the effects of methadone are different from those of other opioids, such as heroin, your body can still get used to it. This means you might need to take more methadone to feel the same effects. This is called tolerance, and it can happen with any other opioids. 

Your body can also become dependent on this drug and other opioids. Your brain relies on the pain relief they bring, and you have withdrawal symptoms if you stop taking them suddenly. Methadone may be packaged and sold under the brand names Methadose, Dolophine, or Physeptone. 

Some people may take methadone with other opioid pain killers, such as oxycodone. High doses or combining methadone with other drugs or painkillers can raise someone’s risk of overdose. These painkillers include oxycontin, hydrocodone (Vicodin), or morphine.

Symptoms of Methadone Overdose

• Vomiting
• Convulsions
• Slow, shallow breathing, known as respiratory depression
• Clammy or bluish skin
• Blue-tinted lips and fingertips
• Extreme fatigue to the point of being unable to stay awake
• Stupor
• Coma
• Death

Combining methadone with other drugs, whether illegal or prescription drugs, can also lead to serious heart problems. These heart problems range from arrhythmia to heart attack.