Methadone for Drug Abuse

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Methadone for Drug Abuse


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Methadone is available as 1 mg, 5 mg, 10 mg, and 25 mg tablets and as an oral solution.

How It Works

Methadone works on parts of the brain and spinal cord to block the "high" caused by using opiates (such as heroin). It also helps reduce cravings and withdrawal symptoms caused by opiate use. The action of methadone is similar to other synthetic (man-made) medicines in the morphine category (opioids). Substances that are derived directly from the opium plant (such as heroin, morphine, and codeine) are known as opiates.

Why It Is Used

Methadone is commonly used to treat addiction to opiates (such as heroin). Taken once a day, methadone eases opiate withdrawal for 24 to 36 hours, decreasing the chance of relapse.

How Well It Works

As a treatment for opiate addiction, methadone reduces the cravings and withdrawal symptoms caused by opiate use by blocking the "high" and preventing the intense euphoric rush of these drugs. This effect allows people to avoid the physical and psychological highs and lows caused by changing levels of opiates in the blood, decreasing the chance of relapse. In some cases of opiate addiction, methadone treatment may be needed for several years or longer.

Side Effects

Methadone causes many side effects, including:

  • Drowsiness.
  • Light-headedness.
  • Weakness and fatigue.
  • Feelings of elation (euphoria).
  • Dry mouth.
  • Difficulty urinating.
  • Difficulty breathing.
  • Constipation, which may be severe.
    • Talk with your doctor about laxative use to prevent constipation.
    • You can prevent constipation at home. Make sure you drink enough fluids. Most adults should drink between 8 and 10 glasses of water or non-caffeinated beverages each day. Include fruits, vegetables, and fibre in your diet each day.
  • Skin reactions, such as irritation, itching, or hives.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Methadone is a long-acting medicine and each dose stays in the body for a long time. For this reason dosages should be adjusted with caution, ideally by an addiction specialist. It may take a couple of days after the medicine is started before the dose of methadone is fully effective.

In some people methadone impairs balance, coordination, or the ability to think. Do not drive or operate any type of equipment if you are taking methadone.

Do not drink alcohol or use other drugs while you are taking methadone.

Methadone can interact with many other medicines. Make sure that your doctor is aware of all of the medicines that you are taking.

Methadone should be used during pregnancy only if the benefits to the mother outweigh the risks to the fetus. Talk with your doctor before using methadone if you are or may be pregnant. This medicine can pass through your body in breast milk and should be avoided while you are breast-feeding.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.


By Healthwise Staff
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Primary Medical Reviewer Andrew Swan, MD, CCFP, FCFP - Family Medicine
Specialist Medical Reviewer Peter Monti, PhD - Alcohol and Addiction
Last Revised October 13, 2010

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.