Benzodiazepine antagonist, non-selective for α1, α2, α3 or α5-containing GABAA receptors. Centrally active upon systemic administration in vivo. Flumazenil, an imidazobenzodiazepine derivative, antagonizes the actions of benzodiazepines on the central nervous system. Flumazenil competitively inhibits the activity at the benzodiazepine recognition site on the GABA/benzodiazepine receptor complex. Flumazenil is a weak partial agonist in some animal models of activity, but has little or no agonist activity in humans.