Obs after Naloxone in Heroin OD

Dr. Mary Callis


As EM docs we see a lot of opiate overdose cases, usually heroin. As a resident learning from attendings, who have different practice patterns, I have noticed varying lengths of observation after naloxone administration. These observations can range from two hours to overnight admissions. This made me want to know the evidence behind observing heroin overdose patients after they received naloxone.


Willman, Michael W. et al. Do heroin overdose patients require observation after receiving naloxone?

Clinical Toxicology. 2017;55(2):81-87. [paper]


Literature review looking at need for ambulance transfer after naloxone and risk of refusal (8 studies), duration of ED observation (5 studies) and effectiveness of naloxone by first responders (15 studies).

  • In heroin overdoses treated in the prehospital environment there were no deaths in 1069 patients who received naloxone but refused transport.

  • In all opiate overdoses only 4 deaths were reported from rebound opioid toxicity among the 5443 patients who were not transferred to the hospital. The NNT to save one life with hospital transport was 1361.

  • A wide range of ED observations times were reported but one study supported a 1-hour observation period as all related adverse events happened during the first hour after naloxone treatment.

  • Few, if any, risks were associated with lay people trained to administer naloxone and the studies reviewed showed high survival rates.


Patients with heroin overdose treated with naloxone are safe for discharge after 1-hour of observation if:

  1. GCS is 15

  2. Vitals signs are normal

  3. No signs of opioid intoxication still present



  • Some points about this meta analysis: while it just came out in February 2017, the articles it references were published before the recent epidemic of fentanyl adulterated heroin. Most of the papers they reviewed also excluded polysubstance intoxications. Dr. Trevonne Thompson, one of our tenured faculty and toxicologists, gave us his thoughts regarding this during conference. He brought up an excellent point that we simply don’t know how long we should observe patients who have used adulterated heroin.

  • There is also the legal consideration of capacity. If a patient has suffered an opiate overdose and were rescued with naloxone, do they have capacity to refuse treatment? Dr. Tim Meehan, another of our toxicologists weighing in via email, said he thinks that the patients lack capacity until the naloxone has worn off. The question of capacity to refuse treatment after an overdose is currently being played out in the news media and potentially the court with the recent lawsuit brought against the ED physician who treated Prince after his first overdose. Per the news reports, after receiving naloxone Prince refused further medical care only to overdose again days later, which resulted in his death.

  • As far as my practice, I’m not sure how many patients will truly fit the criteria for 1-hour observation. The studies reviewed above suggest that unadulterated heroin overdoses are generally safe after routine naloxone treatment. What is still unknown is the duration of observation after an adulterated substance overdose.

  • A final point is that it is very important to observe these patients in a non-stimulated environment and make sure their mental status and vitals are truly normal, rather than saying they have normal vitals when they arrive and may be stimulated.