Title: Flumazenil
CAS Registry Number: 78755-81-4
CAS Name: 8-Fluoro-5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylic acid ethyl ester
Additional Names: ethyl-8-fluoro-5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylate; flumazepil
Manufacturers' Codes: Ro-15-1788
Trademarks: Anexate (Roche); Lanexat (Roche); Mazicon (Roche); Romazicon (Roche)
Molecular Formula: C15H14FN3O3
Molecular Weight: 303.29
Percent Composition: C 59.40%, H 4.65%, F 6.26%, N 13.85%, O 15.83%
Literature References: Imidazodiazepine which selectively blocks the central effects of classic benzodiazepines. Prepn: W. Haefely et al., EP 27214; M. Gerecke et al., US 4316839 (1981, 1982 both to Hoffmann-La Roche). Specific inhibition of benzodiazepine-receptor binding: W. Hunkeler et al., Nature 290, 514 (1981). Electrophysiological study in animals: P. Pole et al., Arch. Pharmacol. 316, 317 (1981). Antagonist, agonist and inverse agonist properties: S. E. File et al., Psychopharmacology 89, 113 (1986). HPLC determn in human plasma: U. Timm, M. Zell, Arzneim.-Forsch. 33, 358 (1983). Clinical reversal of benzodiazepine-induced sedation: A. Darragh et al., Lancet 2, 8 (1981); eidem, ibid. 1042; B. Ricou et al., Br. J. Anaesth. 58, 1005 (1986). Clinical evaluation in drug overdose: G. F. O'Sullivan et al., Clin. Pharmacol. Ther. 42, 254 (1987).
Properties: Crystals from alcohol, mp 201-203°. LD50 in mice, rats (mg/kg): 4000, 1360 i.p.; 4300, 6000 orally (Hunkeler).
Melting point: mp 201-203°
Toxicity data: LD50 in mice, rats (mg/kg): 4000, 1360 i.p.; 4300, 6000 orally (Hunkeler)
Therap-Cat: Benzodiazepine antagonist.
Keywords: Benzodiazepine Antagonist.
Flumecinol Flumedroxone Acetate Flumequine Flumethasone Flumethiazide

Systematic (IUPAC) name
Ethyl 8-fluoro-5-methyl-6-oxo-5,6-dihydro-4H-benzo[f]imidazo[1,5-a][1,4]diazepine-3-carboxylate
Clinical data
Trade names Anexate, Lanexat, Mazicon, Romazicon
AHFS/Drugs.com monograph
Pregnancy cat. B3 (AU) C
Legal status Prescription only
Routes I.V.
Pharmacokinetic data
Metabolism Hepatic
Half-life 7-15 min (initial)
20-30 min (brain)
40-80 min (terminal)
Excretion Urine 90-95%
Feces 5-10%
CAS number 78755-81-4 YesY
ATC code V03AB25
PubChem CID 3373
DrugBank DB01205
ChemSpider 3256 YesY
UNII 40P7XK9392 YesY
KEGG D00697 YesY
Synonyms ethyl 8-fluoro- 5,6-dihydro- 5-methyl- 6-oxo- 4H- imidazo [1,5-a] [1,4] benzodiazepine- 3-carboxylate
Chemical data
Formula C15H14FN3O3 
Mol. mass 303.288 g/mol
 YesY (what is this?)  (verify)
A vial of flumazenil solution for injection

Flumazenil (also known as flumazepil, code name Ro 15-1788) is a GABAA receptor antagonist primarily available by injection only, and the only GABAA receptor antagonist on the market today.

It was first introduced in 1987 by Hoffmann-La Roche under the trade name Anexate, but only approved by the FDA on December 20, 1991. Flumazenil went off patent in 2008 so at present generic formulations of this drug are available. Daily administration of flumazenil by sublingual lozenge and topical cream has been tested positively at Emory University.[1][2] To date the use of this medicine was in rare cases of benzodiazepine overdoses but due to recent studies suggesting the successful treatment of idiopathic hypersomnia with this medicine, the demand of this medicine is estimated to increase drastically. Researchers have recently suggested that the prevalence of idiopathic hypersomnia is higher, at least 1 in 800, which translates to about 400,000 in the U.S. alone thus suggesting a potential market for this drug.[3]