Flumazenil-D3 is an intermediate in the synthesis of Flumazenil Carboxylic Acid-D3 (F500457), which is an isotope labelled form of Flumazenil Carboxylic Acid (F500455); a derivative of Flumazenil (F500450), a benzodiazepine antagonist that can prevent or abolish (at the receptor level) the effects of a benzodiazepine.