Appendix - Methadone Fact Sheet

Methadone Maintenance Treatment: A Community Planning Guide

On this page:

• Therapeutic Use
• Safety of Methadone
• Methadone Pharmacokinetics
• Adverse Effects
• Signs and Symptoms of Opioid Intoxication and Overdose

The following summary of information has been taken from Methadone Maintenance: A Pharmacist's Guide to Treatment (see Recommended Resources). For in-depth information, it is recommended that this guide be consulted.

Therapeutic Use

Methadone is an analgesic which currently in Canada is the only opioid approved for use in long-term treatment of opioid dependence. It is occasionally used for the relief of severe chronic pain. Methadone dosing for pain is different from methadone dosing for opioid dependence.

Safety of Methadone

Studies of long-term administration of methadone have confirmed that it is a medically safe drug. It has been demonstrated that the administration of methadone at doses of 80 to 120 mg per day is not toxic or dangerous to any organ or system after continuous treatment for up to 14 years. When prescribed appropriately, methadone does not impair psychomotor performance (reaction time, attention span) or intellectual capacity.

Methadone Pharmacokinetics

• Absorption: When given orally, methadone is effectively absorbed from the gastrointestinal tract within approximately 30 minutes.
• Distribution: Methadone is extensively bound to plasma proteins.
• Metabolism: Methadone is metabolized in the liver by demethylation and glucuronidation.
• Excretion: Methadone is excreted in the urine and feces both as unchanged methadone and in the form of metabolites.

Adverse Effects

The following is a list of common adverse effects:

• sedation
• sweating
• constipation
• weight changes
• psychoactive effects
• sexual problems
• insomnia
• gastrointestinal problems

Signs and Symptoms of Opioid Intoxication and Overdose

Intoxicated patients may exhibit some of the following:

• euphoria
• dysphoria
• motor retardation
• sedation
• pinpoint pupils
• slowed speech

In addition to the above, overdose is characterized by:

• respiratory depression
• circulatory collapse
• cardiac arrest
• death

The seriousness of methadone intoxication/overdose and its possible consequences cannot be overemphasized. For non-tolerant adults, a single day's maintenance dose of methadone (50-100 mg) can be lethal. For those beginning MMT, starting doses of 40 mg have lead to deaths after three days of treatment. The lethal dose is less if it is taken together with other opioids, alcohol, benzodiazepines or barbiturates. Children may overdose if they mistake the medication for a drink. A 10 to 20 mg dose of methadone can be fatal to a child.

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Methadone Maintenance Treatment: A Community Planning Guide

1. Preface
2. Introduction - How to Use the Guide
3. Methadone Maintenance Treatment - Rationale and Benefits
4. Methadone Maintenance Treatment - Service Components and Delivery Models
5. Critical Stages in the Development of Methadone Maintenance Treatment Services
   1. Identification and Verification of Need
   2. Establishment of a Community Working Group
   3. Methadone Maintenance Treatment Model Development
   4. Implementation
   5. Evaluation
6. Continuity of Care for Methadone Patients
7. Special Treatment Issues
8. Community Development Troubleshooting Guide
9. Appendix - Methadone Fact Sheet
10. References
11. Recommended Resources

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