RESUMO
BACKGROUND: The use of intramuscular adrenaline to treat anaphylaxis is suboptimal, despite being the first-line treatment recommended by national and international anaphylaxis guidelines. Fear of potentially severe side effects may be one of the underlying factors. The aim of this study was to assess the incidence and severity of adverse side effects after the use of adrenaline in anaphylaxis, as well as potential risk factors. METHODS: Observational study based on a multicenter online registry of cases of adrenaline administration for suspected anaphylaxis. RESULTS: 277 registered valid cases were included: 138 (51.49%) female, median age 29 years (12-47), and 6 children under 2 years with a median age of 9 months (1-21). Side effects occurred in 58 cases (21.64%), with tremors, palpitations, and anxiety being the most frequent. There was a significant association of developing side effects with older age, higher dose of adrenaline, or use of the intravenous route. Potentially severe adverse effects (high blood pressure, chest discomfort, or ECG alterations) occurred only in 8 cases (2.99%); in these cases, no differences were found according to age or adrenaline dose, but again, intravenous administration was associated with more severe adverse events. CONCLUSION: This study shows that side effects affect less than 1 in 5 patients who receive adrenaline for an anaphylactic reaction, and are usually mild and transient. Therefore, in an emergency situation such as anaphylaxis, restricting adrenaline administration due to potential adverse effects would, in general, not be justified.