Flumazenil (FMZ)

Flumazenil is a GABAA receptor antagonist primarily available by injection only, and the only GABAA receptor antagonist on the market today. 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. Because the body does not produce endogenous benzodiazepines, flumazenil only creates behavioral effects when administered concurrently with a benzodiazepine receptor agonist or inverse agonist. Flumazenil is a weak partial agonist in some animal models of activity, but has little or no agonist activity in humans. Flumazenil does not antagonize all of the central nervous system effects of drugs affecting GABA-ergic neurons by means other than the benzodiazepine receptor and does not reverse the effects of opioids.