Perhaps unsurprisingly, Narcan (naloxone) dosing is not a one size fits all proposition. Given the increased prevalence of opiate abuse I felt that it was important to discuss some of the nuances of Narcan dosing. A special thanks goes out to Drs. Berkeley Bennett and Andrea Rinderknecht, Pediatric Emergency Medicine attendings both, for their gathering of this information.

How do we know whether or not we should give Narcan?

Overall the best predictor of opioid intoxication is a respiratory rate <12. But numerous symptoms should be considered including the usual suspects like bradycardia, decreased tidal volume (also hypoventilation). Note that patients who don’t have miosis of the pupils can still have opioid intoxication.

What is the main goal of Narcan administration?

To quote a colleague of mine, “Narcan doesn’t save lives, it just prevents procedures.” The procedure in question is generally endotracheal intubation. So, the true goal is adequate ventilation not a normal level of consciousness.

How exactly do I dose it?

Narcan is most certainly a medicine that you can dose in a few different ways. Here are some general pearls:

  • The range is 0.4 to 2mg IV or IM in kids or adults
  • 4mg/0.1mL concentration of intranasal solution is available
  • If the patient is peri-arrest, consider a higher dose
  • The effect is almost immediate, and one can re-dose every 2-3 minutes up to 8mg
  • The maintenance dose (for infusion) is 2/3 of the dose at which you had an effect, infused over 1 hour. An example: A bolus dose of 1mg IV had good effect, therefore give 1mg/hr IV as an infusion
  • Some paramedics and Emergency Medicine physicians will titrate in small aliquots. This is generally accomplished with 0.4 mg Narcan in 10 mL NS netting a concentration of 0.04 mg/mL. This is typically given 1-2 mL at a time.

Any thing else we should know, since that was as clear as mud?

  • Patients who use combination of heroin and fentanyl may require higher doses of Narcan (up to 8mg)
  • Patients may be combative or at least surly with complete, abrupt reversal – so in an effort to stabilize you may elect to go with a lower initial dose for this reason.
  • There is generally no downside to giving Narcan – seizures are highly unlikely and pulmonary edema has been seen in case reports.