Bretazenil

Bretazenil

Clinical data
ATC code	none
Pharmacokinetic data
Biological half-life	2.5 hours
Identifiers
IUPAC name tert-butyl-8-bromo-11,12,13,13a-tetrahydro-9-oxo-9H-imidazo(1,5-a)-pyrrolo(2,1-c)(1,4)benzodiazepine-1-carboxylate
CAS Number	84379-13-5 Y
PubChem CID	107926
IUPHAR/BPS	4146
ChemSpider	97049 Y
UNII	OSZ0E9DGOJ
ChEMBL	CHEMBL366947 Y
Chemical and physical data
Formula	C19H20BrN3O3
Molar mass	418.284 g/mol
3D model (Jmol)	Interactive image
SMILES O=C(OC(C)(C)C)c1ncn2c4c(C(=O)N3[C@H](c12)CCC3)c(Br)ccc4
InChI InChI=1S/C19H20BrN3O3/c1-19(2,3)26-18(25)15-16-13-8-5-9-22(13)17(24)14-11(20)6-4-7-12(14)23(16)10-21-15/h4,6-7,10,13H,5,8-9H2,1-3H3/t13-/m0/s1 Y Key:LWUDDYHYYNNIQI-ZDUSSCGKSA-N Y

Bretazenil (Ro16-6028) is an imidazopyrrolobenzodiazepineanxiolytic drug which is derived from the benzodiazepine family, and was invented in 1988. It is most closely related in structure to the benzodiazepine antagonist flumazenil, although its effects are somewhat different. It is classed as a high-potency benzodiazepine due to its high affinity binding to benzodiazepine binding sites where it acts as a partial agonist. Its profile as a partial agonist and preclinical trial data suggests that it may have a reduced adverse effect profile. In particular bretazenil has been proposed to cause a less strong development of tolerance and withdrawal syndrome. 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 GABA_A receptor benzodiazepine receptor complexes. 1,4-benzodiazepines bind only to α₁, α₂, α₃ and α₅GABA_A benzodiazepine receptor complexes.

Bretazenil was originally developed as an anti-anxiety drug and has been studied for its use as an anticonvulsant but has never commercialised. It is a partial agonist for GABA_A receptors in the brain. David Nutt from the University of Bristol has suggested bretazenil as a possible base from which to make a better social drug, as it displays several of the positive effects of alcohol intoxication such as relaxation and sociability, but without the bad effects such as aggression, amnesia, nausea, loss of coordination, liver disease and brain damage. The effects of bretazenil can also be quickly reversed by the action of flumazenil, which is used as an antidote to benzodiazepine overdose, in contrast to alcohol for which there is no effective and reliable antidote.