Podcast 912: Narcan (Naloxone)

Contributor: Taylor Lynch, MD

Educational Pearls:

Opioid Epidemic- quick facts

• Drug overdoses, primarily driven by opioids, have become the leading cause of accidental death in the U.S. for individuals aged 18-45.

• In 2021, opioids were involved in nearly 75% of all drug overdose deaths

• The rise of synthetic opioids like fentanyl, which is much more potent than heroin or prescription opioids, has played a major role in the increase in overdose deaths

What is Narcan AKA Naloxone?

• Competitive opioid antagonist. It sits on the receptor but doesn’t activate it.

When do we give Narcan?

• Respiratory rate less than 8-10 breaths per minute

Should you check the pupils?

• An opioid overdose classically presents with pinpoint pupils BUT…

• Hypercapnia from bradypnea can normalize the pupils

• Taking other drugs at the same time like cocaine or meth can counteract the pupillary effects

• Basilar stroke could also cause small pupils, so don’t anchor on an opioid overdose

How does Narcan affect the body?

• Relatively safe even if the patient is not experiencing an opioid overdose. So when in doubt, give the Narcan.

• What if the patient is opioid naive and overdosing?

• Use a large dose given that this patient is unlikely to withdraw

• 0.4-2 mg every 3-5 minutes

• What if the patient is a chronic opioid user

• Use a smaller dose such as 0.04-0.4 mg to avoid precipitated withdrawal

How fast does Narcan work?

• Given intravenously (IV), onset is 1-2 min

• Given intranasal (IN), onset is 3-4 min

• Given intramuscularly (IM), onset is ~6 min

• Duration of action is 60 mins, with a range of 20-90 minutes

How does that compare to the duration of action of common opioids?

• Heroine lasts 60 min

• Fentanyl lasts 30-60 min, depending on route

• Carfentanyl lasts ~5 hrs

• Methadone lasts 12-24 hrs

• So we really need to be conscious about redosing

How do you monitor someone treated with Narcan?

• Pay close attention to the end-tidal CO2 to ensure that are ventilating appropriately

• Be cautious with giving O2 as it might mask hypoventilation

• Watch the respiratory rate

• Give Narcan as needed

• Observe for at least 2-4 hours after the last Narcan dose

• Larger the dose, longer the observation period

Who gets a drip?

• If they have gotten ~3 doses, time to start the drip

• Start at 2/3rds last effective wake-up dose

Complications

• Flash pulm edema

• 0.2-3.6% complication rate

• Might be from the catecholamine surge from abrupt wake-up

• Might also be from large inspiratory effort against a partially closed glottis which creates too much negative pressure

• Treat with BIPAP if awake and intubation if not awake

Should you give Narcan in cardiac arrest?

• Short answer no. During ACLS you take over breathing for the patient and that is pretty much the only way that Narcan can help

• Just focus on high quality CPR

References

• https://nida.nih.gov/research-topics/trends-statistics/overdose-death-rates#:~:text=Drug%20overdose%20deaths%20involving%20prescription,of%20deaths%20declined%20to%2014%2C716.

• Elkattawy, S., Alyacoub, R., Ejikeme, C., Noori, M. A. M., & Remolina, C. (2021). Naloxone induced pulmonary edema. Journal of community hospital internal medicine perspectives, 11(1), 139–142. https://doi.org/10.1080/20009666.2020.1854417

• van Lemmen, M., Florian, J., Li, Z., van Velzen, M., van Dorp, E., Niesters, M., Sarton, E., Olofsen, E., van der Schrier, R., Strauss, D. G., & Dahan, A. (2023). Opioid Overdose: Limitations in Naloxone Reversal of Respiratory Depression and Prevention of Cardiac Arrest. Anesthesiology, 139(3), 342–353. https://doi.org/10.1097/ALN.0000000000004622

• Yousefifard, M., Vazirizadeh-Mahabadi, M. H., Neishaboori, A. M., Alavi, S. N. R., Amiri, M., Baratloo, A., & Saberian, P. (2019). Intranasal versus Intramuscular/Intravenous Naloxone for Pre-hospital Opioid Overdose: A Systematic Review and Meta-analysis. Advanced journal of emergency medicine, 4(2), e27. https://doi.org/10.22114/ajem.v0i0.279

Summarized by Jeffrey Olson MS2 | Edited by Meg Joyce & Jorge Chalit, OMSII