15. Opioid Overdose

Clinical Features

  • Depressed mental status.
  • Decreased respiratory rate (best predictor of opioid toxicity).
  • Decreased tidal volume.
  • Decreased bowel sounds.
  • Miotic (constricted) pupils.

Agent specific toxicities:

  • Buprenorphine: induces withdrawal in patients with full agonists in their system.
  • Fentanyl: short acting, but can have long stores in prolonged use.
    • Non-prescribed fentanyl often substituted with compounds with longer duration.
  • Loperamide: QRS and QT interval prolongation, wide-complex tachycardia.
  • Meperidine: seizure, serotonin toxicity.
  • Methadone: long acting, QT interval prolongation, Torsades de pointes.
  • Tramadol: seizure.

Pharmacokinetics

Opioid

Serum half-life (hours)

Equivalence to morphine 10 mg IV

Morphine

~2

10 mg IM, IV, subQ

30 mg PO

Codeine

~3

75 mg IM, IV, subQ

130-200 mg PO

Hydromorphone

~2.5

1.5 mg IM, IV, subQ

7.5 mg PO

Oxycodone

~2.5

20-30 mg PO

Hydrocodone

~4.25

30 mg PO

Diacetylmorphine

 

5 mg subQ

Meperidine

~3.2

75-100 mg IM, subQ

300 mg PO

Methadone

~27

10 mg IM, IV, subQ

Variable PO equivalence

Tramadol

~5.5

50-100 mg PO

Fentanyl

~3.7

0.05-0.1 mg IM, IV, subQ

Buprenorphine

~2.33

0.3-0.4 mg IM, IV

  1. mg SL

 

Management

  • Pulse oximetry.
  • Monitor end-tidal CO2.
  • Obtain core temperature.
  • Perform trauma exam.
  • Check FSBG, acetaminophen level if concern for combined product use (Norco, Percocet), CK.
  • EKG.

Treatment:

  • Supplemental oxygen for oxygen saturation <92%.
  • Naloxone: goal is adequate ventilation, not normal consciousness; may be given IV, IM, IN, subQ.
    • Apneic patient: 0.2-1 mg IV.
    • Cardiopulmonary arrest patient: 2 mg IV.
    • Spontaneously breathing: 0.04-0.05 mg IV.
      • Titrate dose every few minutes until RR >12.
      • May start naloxone infusion (2/3 of total initial dose required to re-start breathing, given every hour).
    • Side effects:
      • Naloxone can cause ARDS because rapid withdrawal in setting of elevated pCO2 causes catecholamine surge, increased afterload and resulting in flash interstitial edema.
  • In those with OUD, offer methadone or buprenorphine after overdose resolved.

Disposition:

  • For most opioids: monitor patient for 2-3 hours after last naloxone dose.
  • Monitor for extended periods if long-acting opioid (methadone) used or high dose intra-nasal naloxone used for reversal (2-4 mg IN).

 

Clarke SF, Dargan PI, Jones AL. Naloxone in opioid poisoning: walking the tightrope. Emerg Med J 2005; 22(9): 612-6

Goldfrank’s Toxicologic Emergencies, 9th ed 2010.

Poisoning and Drug Overdose, 6th ed. 2012.