Adrenaline
Adrenaline is the cornerstone of acute pharmacotherapy for anaphylaxis and has been used for more than 100 years. A number of reviews have examined the benefits of adrenaline,11Ring J, Klimek L, Worm M. Adrenaline in the acute treatment of anaphylaxis. Dtsch Arztebl Int 2018;115(31-32):528–534. but these mainly reported studies at high risk of bias. Our review only included comparative studies or consecutive case series with at least 20 participants, but robust studies comparing adrenaline versus no adrenaline are unrealistic because it is not ethical to withhold adrenaline in an emergency.
We identified no eligible studies comparing adrenaline versus no adrenaline in terms of mortality or most other outcomes. Two case-control studies reported on biphasic reactions in children, but it is unclear whether adrenaline prevents biphasic anaphylactic reactions because the certainty of evidence is very low. One study found a non-statistically significant reduction of 9% and the other a significant reduction of 18% (odds ratio (OR) 0.08, 95% CI 0.014 to 0.43, see Table 3 and supplement S5a).22Manuyakorn W, Benjaponpitak S, Kamchaisatian W, Vilaiyuk S, Sasisakulporn C, Jotikasthira W. Pediatric anaphylaxis: triggers, clinical features, and treatment in a tertiary-care hospital. Asian Pac J Allergy Immunol 2015;33(4):281-8.,33Mehr S, Liew WK, Tey D, Tang ML. Clinical predictors for biphasic reactions in children presenting with anaphylaxis. Clin Exp Allergy 2009;39(9):1390-1396.