Opioid use disorder

Background

• A substance use disorder involving heroin, fentanyl, or other opioid medications
• For reference, 1 point of street fentanyl is 100 mg, which is usually 4.4 mg of pure fentanyl

Epidemiology

• The risk of OUD among patients treated with opioids for chronic pain is around 8 to 30%

Management

• Precipitated withdrawal more dangerous than natural withdrawal

Acute Overdose

• First give boluses of naloxone 0.04mg to 0.08mg IV to improve respiratory depression escalated quickly q2-3 minutes up to 0.4, 2, 4, 10, 15mg (start low and go fast)
• Then start infusion of 2/3 the effective dose per hour
• QRS and QT lengthening by blocking Na and K channels
  • May need repeated defibrillation, overdrive pacing, or ECMO

Opioid Substitution Therapy (OST)

• Recommend Suboxone first-line
• Methadone second-line
• Slow-release opioids such as Kadian third-line

Prevention

• Follow safe prescribing practices
• Risk assessment
  • Consider their personal and family history of psychiatric illness and substance use disorder
  • Consider their social history, including their living situation, safety of housing, personal safety, children or dependents, and social supports
  • Can use tools such as the opioid risk tool or SOAPP-R as a more formal risk assessment
  • Physical exam, looking for signs of substance use and its complications
  • Bloodwork, including liver function tests, hemoglobin, and MCV

Further Reading

• Management of opioid use disorders: a national clinical practice guideline. CMAJ. 2018;190(9):e247-e257. doi: 10.1503/cmaj.170958
• Opioid Agonist Therapy:A Synthesis of Canadian Guidelines for Treating Opioid Use Disorder. 2021. Available at: https://www.camh.ca/-/media/files/professionals/canadian-opioid-use-disorder-guideline2021-pdf.pdf