Opioid use disorder

Opioid Use Disorder - The Lowdown on Heroin

• Intoxication Signs:
  • Classic triad: CNS depression, respiratory depression, & miosis (pinpoint pupils).
  • Euphoria, drowsiness (“nodding off”), constipation, slurred speech.
• Withdrawal Signs:
  • Severe flu-like symptoms: mydriasis (dilated pupils), piloerection (“cold turkey”), rhinorrhea, lacrimation, yawning.
  • Nausea, vomiting, diarrhea, myalgias, fever.
  • While not life-threatening, it is intensely dysphoric.

⭐ Pupil size is a critical diagnostic clue: intoxication leads to miosis, while withdrawal results in mydriasis.

• Management:
  • Overdose: Naloxone.
  • Long-term maintenance: Methadone, Buprenorphine, Naltrexone.

Intoxication & Withdrawal - Highs and Lows

• Intoxication (The "High"): A state of CNS depression.

  • Symptoms: Euphoria, sedation, ↓ respiratory rate, miosis (pinpoint pupils).
  • 📌 Classic Triad (CPR): Coma, Pinpoint Pupils, Respiratory Depression.
  • Other signs: Slurred speech, constipation, bradycardia, hypotension.

• Withdrawal (The "Low"): Severe flu-like syndrome.

  • Symptoms: Dysphoria, anxiety, myalgias, nausea, vomiting, diarrhea.
  • Signs: Yawning, lacrimation, rhinorrhea, piloerection ("goosebumps"), mydriasis (dilated pupils), fever.

  ⭐ While intensely uncomfortable, opioid withdrawal is generally not life-threatening.

• Clinical Timeline:

Diagnosis & Overdose - Spotting and Stopping

• Diagnosis (DSM-5): A problematic pattern of opioid use leading to significant impairment, with ≥2 criteria over 12 months.

  • Key features: Tolerance, withdrawal, craving, and using larger amounts than intended.

• Overdose Triad:

  • CNS Depression (Altered Mental Status)
  • Respiratory Depression (↓RR) - most life-threatening
  • Miosis (pinpoint pupils)

⭐ Naloxone has a shorter half-life than most opioids (e.g., methadone). Patients can re-sedate after initial reversal. Continuous monitoring and repeat dosing may be necessary.

Maintenance Therapy - Staying the Course

• Goal: Reduce cravings, prevent relapse, and decrease harm associated with illicit opioid use.
• First-Line Agents:
  • Methadone: Long-acting full µ-opioid agonist. Dispensed at specialized clinics. Monitor for QTc prolongation.
  • Buprenorphine: Partial µ-opioid agonist with a ceiling effect on respiratory depression, making it safer. Can be prescribed in office settings. Often combined with naloxone (Suboxone) to deter injection.
• Second-Line Agent:
  • Naltrexone: Long-acting opioid antagonist. Blocks the euphoric/sedative effects of opioids. Patient must be opioid-free for 7-10 days prior to initiation.

⭐ Exam Favorite: Initiating naltrexone in a patient who is still physically dependent on opioids can precipitate severe and abrupt withdrawal symptoms.

High‑Yield Points - ⚡ Biggest Takeaways

• Opioid intoxication triad: respiratory depression, altered mental status, and miosis (pinpoint pupils).
• Withdrawal presents with severe flu-like symptoms: mydriasis, yawning, lacrimation, and piloerection.
• Naloxone is the primary antidote for acute overdose, acting as a competitive antagonist.
• Long-term management includes methadone (long-acting agonist) and buprenorphine (partial agonist).
• Naltrexone, an antagonist, is used for relapse prevention in detoxified patients.