• Naloxone is a pure opioid antagonist that exerts its effect by competitive inhibition at the opioid receptor sites. It prevents or reverses the effects of opioids, including respiratory depression, sedation and hypotension. In the absence of opioids it exhibits essentially no pharmacological activity.

Pharmacology Review

  • Reversal of respiratory depression in a suspected narcotic overdose.
  • Hypersensitivity to Naloxone
Precautions / Notes
  • Polypharmacy overdose.
  • Naloxone half-life may be less than that of a longer acting opioids (e.g. methadone, diphenoxylate, codeine).
  • Response to Naloxone is rapid, reconsider diagnosis if there is a failure to respond to 2mg Naloxone.
  • Patients may be aggressive post Naloxone and administration due to hypoxia. Scene safety and personal safety are paramount.


  • IM/IV/IO:
    • 0.4-0.8mg (400-800 mcg) repeat dose every 2 minutes as required, titrated to clinical response.
  • IN:
    • One spray of Nyxoid® into nostril.
    • Repeat at 2 minutes in opposite nostril if the patient does not respond.


  • IM/IV/IO:
    • 0.01mg/kg (10mcg/kg, maximum dose 0.4mg (400 mcg), repeat every 2 minutes minutes as required, titrated to clinical response.
    • If high suspicion of overdose, a 0.1mg/kg (100mcg/kg) dose (maximum 2mg) may be given following a lack of response to initial dose.
  • IN:
    • One spray of Nyxoid® into nostril.
    • Repeat dose after 2 minutes if patient does not respond.
Special Considerations

Withdrawal symptoms such as:

  • Aggression
  • Agitation
  • Nausea/vomiting
  • Dilated pupils and lacrimation

Take-Home-Naloxone (THN)

  • For patients that have required Naloxone, every attempt should be made to convince the 'at risk' patient to be transported to a healthcare facility.
  • Where attempts prove futile, IN Naloxone - Nyxoid® could be left with the patient. This is to avoid the risk of opioid related respiratory depression due to the short half-life of Naloxone.
  • In such circumstances please ensure to document leaving Nyxoid® with the person or a responsible other person in the PnT / ePCR.
  • Due to our SASA requirements, clinicians cannot supply scheduled medicines to persons who are not St John WA patients.


0.4mg (400microg) in 1ml vial


Each device of Nyxoid nasal spray contains one spray (100µL). Each dose of 100µL contains 1.8mg naloxone.
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