Iomazenil

Iomazenil (also known as Ro16-0154, INN, USAN; benzodine) is an antagonist and partial inverse agonist of benzodiazepine and a potential treatment for alcohol use disorder. The compound was introduced in 1989 by pharmaceutical company Hoffmann-La Roche as an Iodine-123-labelled SPECT tracer for imaging benzodiazepine receptors (GABA_A receptors) in the brain. Iomazenil is an analogue of flumazenil (Ro15-1788).^[1]

Iomazenil

Clinical data
Other names	Ro 16-0154
Identifiers
IUPAC name ethyl 7-iodanyl-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylate
CAS Number	127985-21-1 Y 127396-36-5 (123I)
PubChem CID	65959
ChemSpider	59362
UNII	7DVX185FLQ 123I: B851121553
ChEMBL	ChEMBL2105020
CompTox Dashboard (EPA)	DTXSID00155549
Chemical and physical data
Formula	C15H14123IN3O3
Molar mass	407.290 g/mol
3D model (JSmol)	Interactive image
SMILES CCOC(=O)c1c2n(cn1)-c3cccc(c3C(=O)N(C2)C)I
InChI InChI=1S/C15H14IN3O3/c1-3-22-15(21)13-11-7-18(2)14(20)12-9(16)5-4-6-10(12)19(11)8-17-13/h4-6,8H,3,7H2,1-2H3/i16-4 Key:FRIZVHMAECRUBR-KIWWSDKQSA-N

Use in brain research

¹²³I-labelled iomazenil can be used to image epileptic seizure foci as an alternative to ¹⁸F-fludeoxyglucose PET imaging.^[2][3]

The effect of iomazenil of reducing levels of GABA in the brain was used by researchers to exacerbate symptoms in patients with schizophrenia in a laboratory study, supporting the theory that a GABA deficiency underlies that disease.^[4]

Alcohol treatment

Researchers at Yale University and Veterans Affairs Connecticut Healthcare System have been testing iomazenil as a potential treatment for drunkenness due to its ability to bind alcohol receptors in the brain.^[5]

See also

• GABA_A receptor negative allosteric modulator
• GABA_A receptor § Ligands