– Bretazenil, also known as Ro 16-6028, is GABA A receptor agonist potentially for the treatment of anxiety disorders. Bretazenil differs from traditional 1,4-benzodiazepines by being a partial agonist and because it binds to ?1, ?2, ?3, ?4, ?5 and ?6 subunit containing GABAA receptor benzodiazepine receptor complexes. 1,4-benzodiazepines bind only to ?1, ?2, ?3 and ?5 GABAA benzodiazepine receptor complexes.