Recommended Naloxone (Narcan) Dosing for Adults
The recommended dose of naloxone for adults with suspected opioid overdose is 0.4 mg to 2 mg intravenously, which may be repeated every 2-3 minutes until respiratory function improves. 1
Route-Specific Dosing
Intravenous Administration (Preferred in Emergency)
- Initial dose: 0.4-2 mg IV 2
- Repeat every 2-3 minutes as needed until respiratory function improves 1
- If no response after 10 mg total, question opioid-induced toxicity diagnosis 2
Intramuscular/Subcutaneous Administration
- Use if IV access is unavailable 2
- Same dosing as IV: 0.4-2 mg 2
- Intramuscular is highly effective and used in 91.9% of prehospital cases in some studies 3
Intranasal Administration
- Standard dose: 2 mg (as 2 mg/mL concentration) 1
- Higher-concentration intranasal naloxone (2 mg/mL) has similar efficacy to intramuscular naloxone 4
- Lower doses (0.4 mg) may be equally effective with fewer adverse effects in prehospital settings 5
Clinical Scenarios
Opioid Overdose
- Initial dose: 0.4-2 mg IV, IM, or SC 2
- Repeat every 2-3 minutes if needed 1
- Higher doses may be needed for potent synthetic opioids 1
Postoperative Opioid Depression
- Lower doses are usually sufficient: 0.1-0.2 mg IV increments 2
- Titrate to desired effect (adequate ventilation and alertness without significant pain) 2
Monitoring After Administration
- Naloxone's duration of action is only 30-45 minutes, which is shorter than many opioids 1
- Patients must be observed for at least 2 hours after the last dose of naloxone 1
- Longer observation periods are required for long-acting opioid overdoses 1
- Continuous monitoring is essential after administration 1
Important Considerations
Potential Adverse Effects
- Precipitated withdrawal in opioid-dependent individuals 1
- Symptoms may include agitation, hypertension, tachycardia, and vomiting 1
- Lower doses (0.04-0.4 mg) may minimize withdrawal symptoms in dependent patients 1
Special Populations
- Elderly patients may require dose reduction 6
- Caution in patients with history of chronic opioid use due to risk of acute withdrawal 6
Pitfalls to Avoid
- Inadequate dosing when dealing with potent synthetic opioids 1
- Premature discharge after naloxone response without adequate observation 1
- Focusing on awakening rather than adequate ventilation 1
- Delaying CPR while searching for naloxone in cardiac arrest patients 1
Intravenous Infusion
- May be diluted in 0.9% sodium chloride or 5% dextrose solution 2
- 2 mg in 500 mL provides concentration of 0.004 mg/mL 2
- Use mixtures within 24 hours 2
- Titrate administration rate according to patient response 2
Naloxone is a safe drug over a wide dose range (up to 10 mg), but careful monitoring is essential due to its shorter duration of action compared to many opioids 7.