Overdose
Intoxicated presentations
Analgesia and anaesthesia
Diversion of methadone
Pregnancy and lactation
Polydrug use
HIV, hepatitis B and C
Psychiatric comorbidity

Overdose

Signs and symptoms of methadone overdose:
  • Pinpoint pupils
  • Sedation/coma
  • Unsteady gait, slurred speech
  • Hypotension
  • Bradycardia
  • Hypoventilation
Note: Symptoms may last for 24 hours or more. Death generally occurs from respiratory depression.
  • Administration of methadone in the morning will ensure peak methadone concentrations occur when patients are normally awake and other people may be available.
  • Naloxone should be given as a prolonged infusion when treating methadone overdose.
  • Patients thought to have taken a methadone overdose require prolonged observation.

Intoxicated presentations

  • Patients who appear intoxicated with CNS depressant drugs should not be given their usual methadone dose or a takeaway dose at that time. They can be asked to re-present later when no longer intoxicated.
  • If intoxication is evident but appears mild the patient may be given a reduced dose but only after being reviewed by the prescriber.
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Analgesia and anaesthesia

Analgesic requirements for patients on methadone:
  • Consider non-opioid analgesics (NSAIDs) Where parenteral analgesics are required, consider ketorolac, (Toradol®) or tramadol (Tramal®).
  • Management of acute pain in hospital for patients on Methadone Maintenance Treatment:
    • Patients in MMT should receive analgesia in the same way as for other patients. This includes the use of injectable and patient controlled analgesia.
    • Patients taking methadone frequently require larger doses of opioid analgesia for adequate pain relief.
    • Partial agonists such as buprenorphine should be avoided as they may precipitate withdrawal symptoms.
  • Patients on methadone may require higher doses of anaesthetic agents in the event of dental or surgical procedures.

Diversion of methadone

The risk of diversion of prescribed methadone can be reduced by:
  • Ensuring that, in general, methadone is consumed under supervision.
  • Careful selection and monitoring of patients eligible to receive takeaway doses taking into account the patient's stability, reliability and progress in treatment.
  • Limiting the number of consecutive takeaway doses.

Pregnancy and lactation

Antenatal and postnatal care should be managed in collaboration with specialist obstetric services experienced in the management of drug dependency during pregnancy.
  • Naloxone challenge should not be used in pregnant women because this may precipitate miscarriage or premature labour.
  • Pregnant women should be maintained on an adequate dose of methadone, to achieve stability and prevent relapse or continued illicit drug use.
  • If dose reductions of methadone or detoxification are to be undertaken during pregnancy these should occur in the second trimester only if the pregnancy is stable.
    • In most instances, dose reductions of 2.5mg-5 mg per week are considered safe.
  • The bioavailability of methadone is decreased in the later stages of pregnancy. It may be necessary to divide the daily dose and possibly to increase the dose in the third trimester.
  • Breast milk contains only small amounts of methadone and mothers can be encouraged to breastfeed.
  • Neonatal care should be managed in collaboration with specialist obstetric or paediatric services experienced in the management of babies born to drug dependent mothers.

Polydrug use

It is recommended that specialist advice be sought when treating patients at high risk from polydrug use especially where sedatives are involved.

HIV, hepatitis B and C

  • Methadone treatment programs should ensure that HIV positive patients have access to specialist HIV medical care so that the patient's health may be monitored and appropriate treatment provided as required.
  • Patients who are acutely infected with Hepatitis B or who are chronic carriers should be referred to a gastroenterologist for specialist assessment and followup.
  • Patients who are Hepatitis C antibody positive should be managed in accordance with Hepatitis C, A Management Guide for General Practitioners (RACGP 1999).

Psychiatric comorbidity

  • Many opioid users exhibit symptoms of anxiety and depression at the time of presentation for treatment but this usually improves within weeks of commencing treatment.
  • If clinical depression persists antidepressants may be prescribed. Unless there is a particular indication for tricyclic antidepressants, SSRIs should be preferred.