Bretazenil (Ro16-6028) is an imidazopyrrolobenzodiazepine[1]anxiolytic drug which is derived from the benzodiazepine family, and was invented in 1988. It is most closely related in structure to the GABA antagonist flumazenil, although its effects are somewhat different. It is classified as a high-potency benzodiazepine due to its high affinity binding to benzodiazepine binding sites[2][3] where it acts as a partial agonist.[4] Its profile as a partial agonist and preclinical trial data suggests that it may have a reduced adverse effect profile.[5] In particular bretazenil has been proposed to cause a less strong development of tolerance and withdrawal syndrome.[6] Bretazenil differs from traditional 1,4-benzodiazepines by being a partial agonist and because it binds to α1, α2, α3, α4, α5 and α6 subunit containing GABAA receptor benzodiazepine receptor complexes. 1,4-benzodiazepines bind only to α1, α2, α3 and α5GABAA benzodiazepine receptor complexes.[1]
^Giusti P, Guidetti G, Costa E, Guidotti A (June 1991). "The preferential antagonism of pentylenetetrazole proconflict responses differentiates a class of anxiolytic benzodiazepines with potential antipanic action". The Journal of Pharmacology and Experimental Therapeutics. 257 (3): 1062–8. PMID1675286.
^Finn DA, Gee KW (November 1993). "A comparison of Ro 16-6028 with benzodiazepine receptor 'full agonists' on GABAA receptor function". European Journal of Pharmacology. 247 (3): 233–7. doi:10.1016/0922-4106(93)90190-K. PMID7905829.
^Haefely W, Facklam M, Schoch P, Martin JR, Bonetti EP, Moreau JL, et al. (1992). "Partial agonists of benzodiazepine receptors for the treatment of epilepsy, sleep, and anxiety disorders". Advances in Biochemical Psychopharmacology. 47: 379–94. PMID1324584.
^Kunovac JL, Stahl SM (December 1995). "Future directions in anxiolytic pharmacotherapy". The Psychiatric Clinics of North America. 18 (4): 895–909. doi:10.1016/S0193-953X(18)30030-3. PMID8748388.
^Płaźnik A (1995). "Pharmacology of tolerance to benzodiazepine receptor ligands". Polish Journal of Pharmacology. 47 (6): 489–99. PMID8868371.