Flumazenil, an imidazobenzodiazepine derivative, has been generally used as an antagonist which antagonizes the hypnotic and sedative effects of benzodiazepines at gamma-amino butyric acid receptors. The anesthetic effects induced by benzodiazepine could be reversed effectively and safely by flumazenil alone, and some have recommended diagnostic usage in intensive care unit and emergency unit as well, for suspected benzodiazepine intoxication. Seizures might follow the use of flumazenil. Benzodiazepine overdose patients who have co-ingested tricyclic and tetracyclic antidepressants are especially at risk for this complication. Therefore, flumazenil could be considered in cases in which quick recovery is required and should be administered intravenously in small, incremental doses.