[Adverse events associated with the use of flumazenil in the Emergency Department]

Benzodiazepine poisoning is a frequent cause of attendance in hospital emergency departments (ED). Despite its widespread use, the conditions under which flumazenil is administered and the frequency of adverse effects remain unclear. The objective of this study is to describe the conditions of flumazenil administration, as well as the frequency and associated factors of adverse effects.

A retrospective observational study was conducted, including adult patients treated with flumazenil in 11 EDs during 2023. To assess factors associated with the occurrence of adverse effects, logistic regression analysis was performed, including variables with a p-value <0.100 from a previous univariate analysis.

A total of 798 patients [mean age: 51.4 (SD:21.4) years] were included. Benzodiazepine intoxication was confirmed in 513 (64.3%) patients. Concomitant intoxication with alcohol was present in 22.8% and with tricyclic antidepressants in 5.6%. The median administered dose of flumazenil was 0.75mg (range: 0.12-23.1mg). Continuous infusion was used in 338 (42.4%) patients. Adverse effects related to flumazenil were reported in 63 (7.9%) patients, with agitation or anxiety being the most common. A history of epilepsy [OR:2.85 (1.17-6.90)] and the use of doses greater than 0.5mg [OR:2.14 (1.02-4.68)] were significantly associated with the occurrence of adverse effects.

The administration of flumazenil in EDs is highly heterogeneous and is associated with a significant incidence of adverse effects. A history of epilepsy and higher doses of flumazenil are associated with an increased risk of adverse events.