What is the recommended dosage of naloxone (opioid antagonist) for adults?

Recommended Dosage of Naloxone for Adults

The recommended initial dose of naloxone for opioid overdose in adults 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 (IV) Administration

• Initial dose: 0.4 mg to 2 mg 1
• May repeat every 2-3 minutes as needed 1
• If no response after 10 mg total, question diagnosis of opioid-induced toxicity 1
• For postoperative opioid depression: Use smaller doses (0.1 to 0.2 mg) titrated at 2-3 minute intervals 1

Intramuscular (IM) or Subcutaneous (SC) Administration

• Use when IV access is unavailable 2
• Same dosing as IV: 0.4 mg to 2 mg initially 2
• May repeat as needed every 2-3 minutes 2

Intranasal (IN) Administration

• Most studies used a fixed dose of 2 mg, repeated in 3-5 minutes if necessary 3

Special Considerations

Opioid-Dependent Patients

• Consider lower initial doses (0.04-0.4 mg) to avoid precipitating severe withdrawal 3, 4
• Withdrawal symptoms may include hypertension, tachycardia, vomiting, agitation, and drug cravings 3
• Cautious dosing is warranted as high-dose naloxone may cause catecholamine release leading to pulmonary edema and cardiac arrhythmias in patients treated for severe pain 5

Duration of Action

• Half-life of naloxone is 30-45 minutes 3
• Supplemental doses may be required after 20-30 minutes 3
• The effect of naloxone may wear off before the opioid effect, requiring continued monitoring 5
• Repeat doses or continuous infusion may be necessary for long-acting opioids 2

Continuous Infusion

• May dilute 2 mg naloxone in 500 mL of 0.9% sodium chloride or 5% dextrose (concentration: 0.004 mg/mL) 2
• Use within 24 hours 2
• Titrate rate according to patient response 2

Common Pitfalls to Avoid

1. Delaying CPR while searching for naloxone in cardiac arrest patients 4
2. Premature discharge after naloxone response without adequate observation 4
3. Focusing on awakening rather than adequate ventilation 4
4. Inadequate dosing when dealing with potent synthetic opioids 4
5. Failing to recognize that naloxone will not reverse effects of non-opioid substances in polysubstance overdose 4
6. Administering too high a dose in opioid-dependent patients, causing severe withdrawal 6

Treatment Algorithm

1. Assess responsiveness and breathing
2. Begin rescue breathing if necessary
3. Administer appropriate naloxone dose based on route and patient status
4. Reassess after 2-3 minutes
5. Repeat dosing as needed until adequate respiratory function is achieved
6. Monitor for at least 1-2 hours after last dose due to naloxone's shorter duration compared to many opioids 4

Naloxone is a safe medication with a wide therapeutic window, but careful dose titration is important to balance reversal of respiratory depression with minimizing withdrawal symptoms in opioid-dependent individuals.