Opioid Use Disorder Rx - Taming the Dragon
- MAT is cornerstone for OUD. 📌 MAT: Methadone, Buprenorphine, Naltrexone ("My Best New-life").
| Drug | MOA | Key SEs | CIs / Key Points | Doses (Oral unless stated) |
|---|---|---|---|---|
| Methadone | Full μ-agonist | QTc prolong, sedation, constipation | Risk of resp. depression. ECG monitoring. | Start 10-30mg; Maint: 60-120mg/day |
| Buprenorphine | Partial μ-agonist | Precipitated withdrawal, headache, nausea | Induce COWS >10-12. Ceiling on resp. depression. Sublingual (SL). | Start 2-4mg SL; Maint: 16-24mg/day (+Naloxone) |
| Naltrexone | μ-opioid antagonist | Hepatotoxicity (dose-related), nausea | Opioid-free 7-10 days (oral), 7-14 (IM). Test dose may be needed. | Oral: 50mg/day; IM: 380mg q4wks |
| %%{init: {'flowchart': {'htmlLabels': true}}}%% | ||||
| flowchart TD |
Start["🩺 OUD Diagnosis
• Opioid use disorder• Clinical assessment"]
Withdrawal["❓ Acute Withdrawal?
• Assess symptoms• COWS score check"]
Manage["⚠️ Manage Withdrawal
• Symptomatic Rx• Buprenorphine start"]
MAT["📋 Select MAT
• Pick therapy type• Patient preference"]
Methadone["💊 Methadone
• Full mu-agonist• Highly regulated"]
Buprenorphine["💊 Buprenorphine
• Partial agonist• Ceiling effect"]
Naltrexone["💊 Naltrexone
• Mu-antagonist• Opioid-free 7-10d"]
Start --> Withdrawal Withdrawal -->|Yes| Manage Withdrawal -->|No/Stabilized| MAT Manage --> MAT MAT --> Methadone MAT --> Buprenorphine MAT --> Naltrexone
style Start fill:#F7F5FD, stroke:#F0EDFA, stroke-width:1.5px, rx:12, ry:12, color:#6B21A8 style Withdrawal fill:#FEF8EC, stroke:#FBECCA, stroke-width:1.5px, rx:12, ry:12, color:#854D0E style Manage fill:#FDF4F3, stroke:#FCE6E4, stroke-width:1.5px, rx:12, ry:12, color:#B91C1C style MAT fill:#FEF8EC, stroke:#FBECCA, stroke-width:1.5px, rx:12, ry:12, color:#854D0E style Methadone fill:#F1FCF5, stroke:#BEF4D8, stroke-width:1.5px, rx:12, ry:12, color:#166534 style Buprenorphine fill:#F1FCF5, stroke:#BEF4D8, stroke-width:1.5px, rx:12, ry:12, color:#166534 style Naltrexone fill:#F1FCF5, stroke:#BEF4D8, stroke-width:1.5px, rx:12, ry:12, color:#166534
> ⭐ Buprenorphine, a partial μ-opioid agonist, has a ceiling effect on respiratory depression, making it safer in overdose than full agonists like methadone.
## Alcohol Use Disorder Rx - Quenching the Fire
Pharmacotherapy manages withdrawal & prevents relapse.
**Withdrawal (CIWA-Ar Guided):**
```mermaid
%%{init: {'flowchart': {'htmlLabels': true}}}%%
flowchart TD
AUD["<b>🍺 AUD Withdrawal</b><br><span style='display:block; text-align:left; color:#555'>• Alcohol cessation</span><span style='display:block; text-align:left; color:#555'>• Clinical onset</span>"]
CIWA["<b>📋 CIWA-Ar Score</b><br><span style='display:block; text-align:left; color:#555'>• Assess severity</span><span style='display:block; text-align:left; color:#555'>• Clinical scale</span>"]
Support["<b>✅ Supportive Care</b><br><span style='display:block; text-align:left; color:#555'>• Hydration therapy</span><span style='display:block; text-align:left; color:#555'>• Close monitoring</span>"]
Benzo["<b>💊 Benzodiazepines</b><br><span style='display:block; text-align:left; color:#555'>• Lorazepam 2-4mg</span><span style='display:block; text-align:left; color:#555'>• Diazepam 5-10mg</span>"]
Taper["<b>👁️ Taper Process</b><br><span style='display:block; text-align:left; color:#555'>• Follow CIWA-Ar</span><span style='display:block; text-align:left; color:#555'>• Slow reduction</span>"]
AUD --> CIWA
CIWA -->|Under 10| Support
CIWA -->|Over 10| Benzo
Benzo --> Taper
style AUD fill:#F7F5FD, stroke:#F0EDFA, stroke-width:1.5px, rx:12, ry:12, color:#6B21A8
style CIWA fill:#FEF8EC, stroke:#FBECCA, stroke-width:1.5px, rx:12, ry:12, color:#854D0E
style Support fill:#F6F5F5, stroke:#E7E6E6, stroke-width:1.5px, rx:12, ry:12, color:#525252
style Benzo fill:#F1FCF5, stroke:#BEF4D8, stroke-width:1.5px, rx:12, ry:12, color:#166534
style Taper fill:#EEFAFF, stroke:#DAF3FF, stroke-width:1.5px, rx:12, ry:12, color:#0369A1
Relapse Prevention Agents:
| Drug | MOA | Key SEs | CIs | Monitoring |
|---|---|---|---|---|
| Naltrexone | μ-Opioid antagonist | Nausea, hepatotoxicity | Opioid use, acute hepatitis | LFTs |
| Acamprosate | NMDA modulator | Diarrhea | Severe renal (CrCl <30) | Renal function |
| Disulfiram | Aldehyde Dehydrogenase inhibitor | Flushing, N/V (with EtOH) | Cardiac disease, psychosis | LFTs |
Agent Selection:
⭐ Disulfiram inhibits aldehyde dehydrogenase, leading to acetaldehyde accumulation if alcohol is consumed.
Nicotine & Other SUDs Rx - Clearing the Smoke & Shadows
Pharmacotherapy for Nicotine Dependence:
| Drug | MOA | Key SEs | CIs | Duration / Key Doses |
|---|---|---|---|---|
| NRT (Patch, Gum etc) | Provides nicotine, ↓withdrawal symptoms & cravings | Local irritation (patch), dyspepsia (gum), hiccups | Recent MI/CVA (caution) | 8-12 weeks, then taper |
| Varenicline | Partial α4β2 nicotinic receptor agonist; ↓cravings & withdrawal symptoms | Nausea, insomnia, abnormal dreams; neuropsychiatric (monitor) | Severe renal impairment (adjust) | Start 1 wk pre-quit. 12-24 wks. Titrate: 0.5mg OD (D1-3)→0.5mg BD (D4-7)→1mg BD (D8+) |
| Bupropion SR | Norepinephrine-dopamine reuptake inhibitor (NDRI); nicotinic antagonist | Insomnia, dry mouth, headache; seizures (dose-dependent) | Seizure d/o, eating d/o (bulimia/anorexia), MAOI use in 14d, abrupt ETOH/BZD withdrawal | Start 1-2 wks pre-quit. 7-12 wks. Max 300mg/day (150mg BD) |
Other SUDs:
- Benzodiazepine Withdrawal: Gradual taper (↓10-25% q 1-2 wks). Switch to long-acting BZD (e.g., diazepam). 📌 Taper Slow, Avoid the Woe.
High‑Yield Points - ⚡ Biggest Takeaways
- Naltrexone (oral/injectable) for opioid & alcohol dependence; CI: acute hepatitis, current opioid use (precipitates withdrawal).
- Disulfiram for alcohol deterrence via acetaldehyde syndrome; monitor LFTs, ensure abstinence before starting.
- Acamprosate for alcohol relapse prevention (GABA/glutamate modulation); renally excreted, safe with liver disease.
- Methadone for opioid maintenance therapy (OMT); risk of QTc prolongation, numerous drug interactions, supervised dispensing.
- Buprenorphine (± naloxone) for OMT; safer in overdose than methadone due to ceiling effect on respiratory depression.
- Varenicline for smoking cessation; highest efficacy, monitor for neuropsychiatric effects and cardiovascular events (rare).
