What the label lists and what reports show
Flumazenil side effects
Flumazenil's FDA label: “Serious adverse events have occurred in all clinical settings, and convulsions are the most common serious adverse events reported.” FAERS holds 849 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is toxicity to various agents (90 reports).
- Generic listed
- Boxed warning
Check it at the source: the flumazenil FDA label on DailyMed (effective June 21, 2024, Hikma Pharmaceuticals USA Inc.); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsSerious adverse events have occurred in all clinical settings, and convulsions are the most common serious adverse events reported.
From the label: adverse reactions, continuedSerious Adverse Reactions Deaths have occurred in patients who received flumazenil in a variety of clinical settings. The majority of deaths occurred in patients with serious underlying disease or in patients who had ingested large amounts of non-benzodiazepine drugs (usually cyclic antidepressants), as part of an overdose. Serious adverse events have occurred in all clinical settings, and convulsions are the most common serious adverse events reported. Flumazenil administration has been associated with the onset of convulsions in patients with severe hepatic impairment and in patients who are relying on benzodiazepine effects to control seizures, are physically dependent on benzodiazepines, or who have ingested large doses of other drugs (mixed-drug overdose) (see WARNINGS ). Two of the 446 patients who received flumazenil in controlled clinical trials for the management of a benzodiazepine overdose had cardiac dysrhythmias (1 ventricular tachycardia, 1 junctional tachycardia). Adverse Events in Clinical Studies The following adverse reactions were considered to be related to flumazenil administration (both alone and for the reversal of benzodiazepine effects) and were reported in studies involving 1875 individuals who received flumazenil in controlled trials. …
Source: FDA drug label, Hikma Pharmaceuticals USA Inc., effective June 21, 2024 (SPL set 436f5616-9626-4b6a-9deb-2986444179d0), via openFDA; the full label on DailyMed
What do FAERS reports show?
849 reports list flumazenil among the medicines taken, each a report of something that happened, not proof the medicine caused it; 170 are coded as a death and 479 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 18 reactions below, 5 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Flumazenil: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions