Adrenaline auto-injectors may not prevent fatal anaphylaxis

Individuals at risk of anaphylaxis—an acute systemic hypersensitivity reaction to an allergen or trigger, typically associated with skin reactions, nausea/vomiting, difficulty breathing, and shock—are often prescribed adrenaline (epinephrine) autoinjectors such as EpiPens.

A recent review published in Clinical & Experimental Allergy finds that these autoinjectors, which people use to self-administer adrenaline into the muscle, can deliver high doses of adrenaline into the blood, but these levels are short-lived and may not be sufficient to save lives in cases of fatal anaphylaxis.

Investigators noted that data from animal and human studies suggests that intravenous adrenaline infusions delivered directly into the blood can prevent fatal anaphylaxis, but adrenaline autoinjectors may have little impact in such deadly cases.

“For effective management of the most severe allergic reactions, adrenaline given by continuous intravenous infusion, with appropriate fluid resuscitation, is likely to be required—how this is safely achieved in the pre-hospital setting remains to be determined,” the authors wrote. This challenge stems from the fact that fatal anaphylaxis is unpredictable and fast. Fortunately, fatality is rare, with a population incidence of 0.03–0.51 per million per year.