What is the dosing of Naloxone (Narcan) as needed (prn) for opioid overdose?

From the Guidelines

Naloxone (Narcan) for opioid overdose should be administered as 0.4-2 mg intravenously, intramuscularly, or subcutaneously, with repeat doses every 2-3 minutes as needed until respiratory function improves, as recommended by the 2015 American Heart Association guidelines update for cardiopulmonary resuscitation and emergency cardiovascular care 1.

Key Considerations

• The ideal dose of naloxone is not known, but an empiric starting dose of 0.04 to 0.4 mg IV or intramuscular (IM) was previously recommended to avoid provoking severe opioid withdrawal in patients with opioid dependency 1.
• For intranasal administration, a fixed dose of 2 mg, repeated in 3 to 5 minutes if necessary, has been used in most studies 1.
• The initial goal of therapy is to restore and maintain patent airway and ventilation, preventing respiratory and cardiac arrest, without provoking severe opioid withdrawal 1.

Administration and Monitoring

• Naloxone can be administered intravenously, intramuscularly, intranasally, or subcutaneously, depending on the rescuer's training and clinical circumstance 1.
• After administering naloxone, it is essential to maintain airway support, monitor vital signs, and arrange immediate medical transport as the patient may experience withdrawal symptoms and require further care.
• Additional doses may be required for potent synthetic opioids like fentanyl or if respiratory depression returns as naloxone's effect (30-90 minutes) wears off before the opioid's effect.

Mechanism of Action

• Naloxone works by competitively binding to opioid receptors, displacing the opioid and temporarily reversing respiratory depression, which is the primary cause of death in opioid overdose 1.

Special Considerations

• Higher initial doses may be needed for synthetic opioids, and continuous monitoring is essential as naloxone's duration of action is shorter than many opioids.
• Naloxone administration may precipitate acute withdrawal syndrome in patients with opioid dependency, with signs and symptoms including hypertension, tachycardia, piloerection, vomiting, agitation, and drug cravings, which can be minimized by using the lowest effective dose of naloxone 1.

From the FDA Drug Label

Usage in Adults: Opioid Overdose—Known or Suspected: An initial dose of 0. 4 mg to 2 mg of naloxone hydrochloride may be administered intravenously. If the desired degree of counteraction and improvement in respiratory functions are not obtained, it may be repeated at two to three minute intervals If no response is observed after 10 mg of naloxone hydrochloride have been administered, the diagnosis of opioid-induced or partial opioid-induced toxicity should be questioned

The dosing of Naloxone (Narcan) as needed (prn) for opioid overdose is:

• Initial dose: 0.4 mg to 2 mg intravenously
• Repeat dose: may be repeated at 2 to 3 minute intervals if desired degree of counteraction and improvement in respiratory functions are not obtained
• Maximum dose: if no response is observed after 10 mg of naloxone hydrochloride have been administered, the diagnosis of opioid-induced or partial opioid-induced toxicity should be questioned 2 2

From the Research

Naloxone Dosing for Opioid Overdose

• The dosing of Naloxone (Narcan) as needed (prn) for opioid overdose can vary depending on the route of administration and the specific product used 3, 4, 5, 6, 7.
• Studies have shown that intramuscular naloxone doses of 0.4 and 0.8 mg are effective and safe in the treatment of opioid overdose in the prehospital setting 6.
• Intranasal naloxone administration has also been shown to be effective in reversing opioid-induced respiratory depression, with doses ranging from 2-4 mg 4, 5, 7.
• The choice of dose and route of administration may depend on various factors, including the patient's clinical presentation and the availability of medical personnel 6.
• It is worth noting that the optimal dosing and route of administration for naloxone may vary depending on the specific context and patient population, and further research is needed to fully determine the best practices for naloxone administration 3, 4, 5, 6, 7.

Route of Administration

• Intramuscular injection is a common route of administration for naloxone, with doses of 0.4-0.8 mg being effective in reversing opioid overdose 6.
• Intranasal administration is also effective, with doses of 2-4 mg being used in various studies 4, 5, 7.
• The choice of route of administration may depend on the availability of medical personnel and the patient's clinical presentation 6.

Dosing Considerations

• The dose of naloxone may need to be titrated based on the patient's response to treatment, with some patients requiring multiple doses 6.
• The use of higher doses of naloxone (e.g. 4 mg) may be associated with a higher risk of adverse events, such as agitation and rebound opioid toxicity 7.
• However, the evidence suggests that the risk of serious adverse events is low, even with higher doses of naloxone 7.