Stabilisation

• seek expert advice
• stabilisation may be undertaken as an outpatient, or as an inpatient (more rapid process)
• in general, not more than 40mg of methadone will be required during the first 24 hour period
• if outpatient stabilisation is undertaken then the initial methadone dose should be based on a clinical assessment of dependence:
  • a first dose of 10-20mg of methadone syrup should be consumed whilst the patient is observed (1) - the patient should then be observed for one hour for evidence of intoxification (some experts suggest that first doses in excess of 20mg should be avoided in case the severity of dependence has been exaggerated and the patient cannot tolerate a high methadone dose (1))
  • the patient should attend the following day - if there is evidence of opioid abstinence syndrome then the dose of methadone syrup should be increased by 10mg. This consumption of this dose should also be observed and the patient should be monitored for one hour
  • this process of stepwise increasing of methadone may need to be repeated further until there is no evidence of opioid abstinence syndrome

Notes (2):

• NICE (2) detail an initial dose of 10-40 mg daily, which is increased by up to 10 mg daily (with a maximum weekly increase of 30 mg) until no signs of withdrawal or intoxication are seen. The usual maintenance dose range is 60-120 mg daily
• initiation of treatment with methadone presents a potential risk of respiratory depression and should be undertaken with care
  • serious respiratory depression may be induced by interactions between methadone and other respiratory depressants such as alcohol, benzodiazepines and the newer non-benzodiazepine hypnotics (Z-drugs), other sedatives or tricyclic antidepressants
  • is a risk of death early in methadone treatment as a result of excessive initial doses, failing to recognise cumulative effects, giving methadone to people with impaired liver function (due to chronic hepatitis) or failing to inform patients of the dangers of overdose if they are using other drugs at the same time
  • relatively slow onset of action and long half-life mean that methadone overdose and toxic effects may become life threatening several hours after a dose is taken
  • during methadone initiation phase, the dose should be adjusted carefully in order to eliminate drug craving and prevent withdrawal while avoiding the risk of intoxication or overdose
    • process needs to be monitored by a doctor or trained nurse, and may require regular visits by the patient to a community prescribing centre
    • review initially should be at least fortnightly, but when the patient is stable, the frequency of medical assessment can be reduced

Reference:

1. Prescribers' Journal (2000); 40 (2):67-76.
2. NICE (January 2007).Methadone and buprenorphine for the management of opioid dependence