Nimetazepam

Nimetazepam

Clinical data
Trade names	Erimin
AHFS/Drugs.com	International Drug Names
Pregnancy category	X
Routes of administration	By mouth
ATC code	N05CD15 (WHO)
Legal status
Legal status	AU: S4 (Prescription only) BR: Class B1 (Psychoactive drugs)[1] CA: Schedule IV DE: Anlage III (Special prescription form required) US: Schedule IV UN: Psychotropic Schedule IV
Pharmacokinetic data
Bioavailability	95%
Metabolism	Liver
Elimination half-life	14–30 hours
Excretion	Kidney
Identifiers
IUPAC name 1-methyl-7-nitro-5-phenyl-3H-1,4-benzodiazepin-2-one
CAS Number	2011-67-8 N
PubChem CID	4496
ChemSpider	4340 Y
UNII	4532264KW6
KEGG	D01593 Y
ChEBI	CHEBI:31912 N
ChEMBL	ChEMBL13341 Y
CompTox Dashboard (EPA)	DTXSID6023369
ECHA InfoCard	100.016.302
Chemical and physical data
Formula	C16H13N3O3
Molar mass	295.298 g·mol−1
3D model (JSmol)	Interactive image
SMILES [O-][N+](C1=CC2=C(C=C1)N(C)C(CN=C2C3=CC=CC=C3)=O)=O
InChI InChI=1S/C16H13N3O3/c1-18-14-8-7-12(19(21)22)9-13(14)16(17-10-15(18)20)11-5-3-2-4-6-11/h2-9H,10H2,1H3 Y Key:GWUSZQUVEVMBPI-UHFFFAOYSA-N Y
NY (what is this?)  (verify)

Nimetazepam (marketed under brand name Erimin and Lavol) is an intermediate-acting hypnotic drug which is a benzodiazepine derivative. It was first synthesized by a team at Hoffmann-La Roche in 1964.^[2] It possesses powerful hypnotic, anxiolytic, sedative, and skeletal muscle relaxant properties. Nimetazepam is also a particularly potent anticonvulsant.^[3] It is marketed in 5 mg tablets known as Erimin, which is the brand name manufactured and marketed by the large Japanese corporation Sumitomo. Japan is the sole manufacturer of nimetazepam in the world. Outside of Japan, Erimin is available in much of East and Southeast Asia and was widely prescribed for the short-term treatment of severe insomnia in patients who have difficulty falling asleep or maintaining sleep. Sumitomo has ceased manufacturing Erimin since November 2015. It is still available as a generic drug or as Lavol.

Nimetazepam was widely prescribed in the 1980s and 1990s, particularly in Japan, Malaysia, Brunei, the Philippines, Thailand, Indonesia, Hong Kong and Singapore. Prescriptions for the drug have decreased dramatically since 2005 due to rampant misuse and addiction. It is primarily used as an anticonvulsant in children. It is also still used in the most severe and debilitating cases of insomnia in an inpatient setting or in short term outpatient treatment. Hypnotic benzodiazepines estazolam and nitrazepam are used more frequently than nimetazepam for this purpose. Antidepressants such as trazodone and mirtazapine or Z-drugs like zopiclone and zolpidem are first line treatment for insomnia.

Although prescriptions for nimetazepam have decreased, abuse of the drug is still significant in Brunei, Singapore, Malaysia, and the Philippines. It is commonly used in combination with methamphetamine and MDMA (Ecstasy) and opiates (especially heroin or morphine). The strict legal restrictions nimetazepam is subject to in Malaysia has made the drug scarce, but many pills sold as nimetazepam in the black market are counterfeit. Diazepam and nitrazepam are among the most commonly prescribed benzodiazepines in the region, and as a result, they are commonly diverted and sold on the black market, often as nimetazepam.

Illicit manufacturing of nimetazepam (sold as Erimin-5) is prevalent in the region. Abuse of nimetazepam continued to rise throughout the 2010s. Seizures of illicitly manufactured Erimin-5 tablets paralleled the seizures of methamphetamine seizures in Malaysia. A small seizure of 46 illicit Erimin-5 tablets were tested for their physical and chemical characteristics. The active ingredient, adulterant, major diluent, and dyes make up the chemical characteristics of a tablet. The results indicated that nimetazepam was the most common active ingredient in the vast majority of the tablets seized. Lactose was detected as a major diluent in the majority of the samples, followed by mannitol and then calcium phosphate dibasic dihydrate. Sunset yellow was found in most of the tablet samples either alone or in combination with other dyes such as tartrazine and ponceau 4R to give the tablets a peach/orange colour. Green tablets in the samples contained brilliant blue and tartrazine dyes. Diazepam, which is primarily an anxiolytic, was the active ingredient in only one tablet out of the 46. Nitrazepam, a powerful sedative-hypnotic, which is also nimetazepams parent drug, was found to be a minor compound together with a caffeine as a major compound in three of the tablets.^[4]

In 2003, 94,200 Erimin-5 tablets were seized in Singapore. The Central Narcotics Bureau's (CNB) laboratory tested the tablets with results that confirmed the tablets were indeed nimetazepam.