• Type: Opioid antagonists, antidote
  • Dosage Forms:
  • Common Trade Names: Narcan

Adult Dosing

Opioid toxicity

  • Bolus (May repeat q3min up to max dose 10mg
    • Apneic or near-apneic - 2mg IV
    • Opioid-naive with minimal respiratory depression - 0.4mg IV
    • Opioid-dependent with minimal respiratory depression - 0.05mg IV
  • Infusion
    • Only give if the patient responded to the bolus and required repeat administration
    • Step 1: Determine the "wake-up dose" or bolus required to wake the pt
    • Step 2: Give 2/3 of the "wake-up dose" per hr; mix in 1L D5W

Pediatric Dosing

  • IV: 0.005 to 0.01mg/kg IV every 2 to 3 minutes as needed to desired degree of reversal
  • If IV route is not available, may administer in divided doses IM

Special Populations

  • Pregnancy Rating: C
  • Lactation: insufficient data
  • Renal Dosing
    • Adult
    • Pediatric
  • Hepatic Dosing
    • Adult
    • Pediatric


  • Allergy to class/drug

Adverse Reactions


  • Metabolism: hepatic
  • Excretion: renal
  • Mechanism of Action: opioid antagonist
  • Onset of action - 1-2min
  • Duration of action - 20-90min (may be less than that of the ingested opioid)
  • For this reason many hospital algorithms call for ~3 hours of ED observation prior to discharge
  • Some small studies have called for decreasing this time frame to 1 hour but there are often adverse events in a significant proportion of these patients (one study showed that 15% of patients had adverse events such as need for supplemental oxygen after attempting discharge at 1 hour)[2].

See Also


  1. Mechanism for Naloxone-Related Pulmonary Edema in Opiate or Opioid Overdose Reversal. August 2015. EBM Consult.
  2. Hospital Observation Upon Reversal (HOUR) With Naloxone: A Prospective Clinical Prediction Rule Validation Study Clemency, B.M., et al, Acad Emerg Med 26(1):7, January 2019