What is the recommended dose of Narcan (naloxone) to reverse an opioid overdose?

Naloxone Dosing for Opioid Overdose Reversal

The recommended initial dose of naloxone for opioid overdose reversal is 0.4 mg to 2 mg intravenously, which may be repeated every 2-3 minutes until respiratory function improves. 1, 2

Dosing Guidelines by Route of Administration

Intravenous Administration (Preferred when available)

• Initial dose: 0.4-2 mg
• May repeat every 2-3 minutes as needed
• If no response after 10 mg total, question opioid-induced toxicity diagnosis 1
• For opioid-dependent patients, consider starting with lower doses (0.04-0.4 mg) to minimize withdrawal symptoms 3, 4

Alternative Routes (When IV access unavailable)

• Intramuscular/Subcutaneous: 0.4-2 mg, may repeat every 2-3 minutes 1
• Intranasal: 2 mg, may repeat in 3-5 minutes if necessary 4
• Nebulized: 2 mg diluted in 3 mL normal saline 4

Treatment Algorithm

1. Assess airway and breathing first

   • Focus on supporting airway and breathing before naloxone administration 4
   • Begin rescue breathing if necessary

2. Administer naloxone based on clinical scenario

   • For respiratory arrest with pulse: Administer naloxone while continuing respiratory support 4
   • For cardiac arrest: Focus on high-quality CPR; naloxone can be given but should not delay CPR 4

3. Reassess after 2-3 minutes

   • If inadequate response, repeat dose
   • Continue until respiratory function improves

4. Post-reversal monitoring

   • Observe for at least 2 hours after the last dose of naloxone 2
   • Monitor for recurrent respiratory depression (naloxone's duration of action is 30-45 minutes, shorter than many opioids) 2

Special Considerations

Opioid-Dependent Patients

• Lower initial doses (0.04-0.4 mg) may minimize withdrawal symptoms while still reversing respiratory depression 3, 4
• Titrate carefully to restore adequate respiration without precipitating severe withdrawal

Long-Acting Opioid Overdose

• May require repeated doses or continuous infusion 4, 2
• Extended observation period recommended 2

Common Pitfalls to Avoid

1. Premature discontinuation of monitoring

   • Naloxone's duration of action (30-45 minutes) is shorter than many opioids, risking recurrent respiratory depression 2

2. Delaying emergency response activation

   • Always activate emergency services; don't delay while awaiting response to naloxone 2

3. Administering excessive doses to opioid-dependent patients

   • Can precipitate severe withdrawal symptoms (hypertension, tachycardia, vomiting, agitation) 4, 3

4. Relying solely on naloxone in cardiac arrest

   • High-quality CPR should take priority over naloxone administration 4, 2

5. Discharging patients too early

   • Patients should be observed until risk of recurrent toxicity is low and vital signs have normalized 4

The evidence consistently supports that naloxone is highly effective for reversing opioid-induced respiratory depression when administered promptly and at appropriate doses. Age may influence dosing requirements, with younger patients potentially needing higher doses 5.