Drug Summary

Naloxone (Narcan®)

Pharmacologic properties:

Naloxone is a competitive mu opioid receptor antagonist. The drug antagonizes the effects of opiates by competing at the same receptor sites. Onset of action is 1-2 minutes, the duration of action is 1-4 hours.


  • Naloxone is indicated for the reversal of narcotic intoxication with respiratory depression
  • Altered mental status (unknown cause)


  • Known hypersensitivity


  • Use caution during administration as patient may become agitated or violent as level of consciousness increases
  • Should be administered cautiously to persons who are known or suspected to be physically dependent on opiates, including newborns of dependent mothers – may precipitate acute withdrawal
  • Naloxone has a relatively short half-life compared to many narcotics, monitor closely for the need to repeat dose
  • Naloxone is not effective against a respiratory depression due to non-opioid drugs
  • Patients who become responsive secondary to naloxone administration are not authorized to refuse medical care - transport all such patients as medically incapacitated

Adverse Reactions:

  • Tremor
  • Agitation
  • Belligerence
  • Pupillary dilation
  • Seizures
  • Sweating
  • Hypertension
  • Hypotension
  • Ventricular tachycardia
  • Pulmonary edema
  • Ventricular fibrillation
  • Nausea
  • Vomiting

Dosage and administration:

  • Adult
    • With respiratory depression
      • 2 mg IV, IO, IM, or intranasal via MAD every 3 min as needed (maximum dose 8 mg)
    • Without respiratory depression
      • 0.4 mg IV, IO, IM, or intranasal via MAD every 3 min as needed (maximum dose 2 mg)
  • Pediatric
    • 0.1 mg/kg IV, IO, IM, or intranasal via MAD (maximum individual dose 2.0 mg)
      • May repeat dose once