Flumazenil is an imidazobenzodiazepine derivative and a benzodiazepine antagonist. Competitive inhibition of GABAA makes it possible to use flumazenil as an antidote to drugs that act like benzodiazepines (e.g., Z-drugs). The rapid onset (two minutes) is useful in cases of overdosing, but also in relieving anesthesia. The effect lasts only about two hours, the long duration of action of benzodiazepines must be considered here. It can also be used in primary hypersomnia.