Opioid use disorder
From IDWiki
Epidemiology
- Risk of addiction ~= 10% for non-cancer (Vowles et al in Pain)
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 third-line
Suboxone (buprenorphine/naloxone)
- Recommended as first-line
- Buprenorphine is partial mu-opioid receptor agonist
- Theoretical ceiling effect
- Strong receptor affinity, displaces other opioids
Full Start
- Precipitates withdrawal, so wait 12-24h for short-acting, 18-36h for long-acting, or after tapering methadone
- Ensure COWS ≥12, then give 4mg, wait a few hours, give another 4mg
- Day 2: 12mg; Day 3: 16mg; discharge and refer to Addictions clinic
Methadone
- Recommended as second-line by Canadian guidelines
