If you had a Mount Rushmore of Emergency Department drugs fentanyl would make a pretty solid case for its inclusion. This synthetic opioid is roughly 100x more potent than morphine. The onset is rapid – two to three minutes. This is in contrast to morphine, which can take up to 20 minutes. The duration of action is relatively short – 30 to 60 minutes. Again, for purpose of comparison, the duration of action of morphine is up to 4 hours. As opposed to other opioids (namely morphine) there is no histamine release.
The risk of hypoxemia and respiratory muscle depression is there of course, but more pronounced when used with other sedative agents (like midazolam). Chest wall rigidity is a rare idiosyncratic reaction that you hope you won’t see, and only responds to paralysis and endotracheal intubation. These patients cannot be bagged! The risk may be increased with large doses (>4 mcg/kg), but it reported to have been seen in doses as low as 1 mcg/kg.
There are two main routes of administration for fentanyl for use in most Pediatric Emergency Department settings. Nebulized, transdermal and oral versions are also available but will not be discussed here.
Intravenous
The dose is generally 1 mcg/kg. IV fentanyl is great for situations where you need rapid control of pain, but don’t want lingering physiologic effects. Consider the trauma patient. Fentanyl and morphine will both treat pain, but only one is short lived and less likely to manifest with adverse physiologic effects when the patient is in the scanner.
Intranasal
IN fentanyl is delivered via a nasal atomizer. The dose is 2 mcg/kg and can result in adequate pain management in under 2 minutes. One study of children with long bone fractures noted equivalence with IV morphine. Especially in situations where you would like rapid pain control without having to place an IV, or if you’re not sure if you will need an IV IN fentanyl can be a great option.
