Opioid Dependence

Continuous compulsion to use opioids despite physical, psychological or social harm due to the use

Aetiology

  • Opioids are a class of drugs that include the illegal drug heroin, synthetic opioids such as fentanyl, and pain relievers available legally by prescription such as codeine

Pathophysiology

  • Opiods are either a natural derivative of opium or a synthetic substance with agonist, partial agonist, or mixed agonist and antagonist activity at opioid receptors
  • A natural high or a drug induced high is mediated by the mesolimbic dopamine pathway - sometimes referred to as the pleasure centre of the brain, with dopamine as the pleasure neurotransmitter

Investigations

Meet ICD-10 criteria of dependence:
  • 3 or more present have been present together at some time during the use of previous year:
    • Strong desire or sense of compulsion to take drug
    • Difficulty in controlling use of substance in terms of onset, termination, or level of use
    • Physiological withdrawal state
    • Evidence of tolerance
    • Progressive neglect of other pleasures/interests because of use/effects of substance
    • Persistence with use despite clear evidence of harmful consequences

Management

Pharmacological management

  • Opioid replacement with Mu receptor agonists - methodone (full agonist) , buprenorphine (partial agonist)
    • Choice of opiate substitute depends on patient factors e.g. overdose risk (buprenorphine may have a lower risk of overdose)
    • NICE recommends that, if both drugs are equally suitable, methadone should be prescribed as first choice
  • Stages of opiod replacement:
      1. Induction
      1. Optimisation
      1. Maintenance
      1. Reduction

Additional features of management

  • Psycho-social intervention
  • Counselling
  • Input from other agencies