Nimetazepam CAS: 2011-67-8 hypnotic tranquilizer

Nimetazepam is a medium acting hypnotic, a benzodiazepine derivative. It was first synthesized in 1964 by a team of Hoffmann-La Roche. It has powerful hypnotic, anti-anxiety, calming and skeletal muscle relaxation effects. Nimetazepam is also a particularly effective anticonvulsant. It is sold as a 5-milligram tablet called Erimin, a brand name made and sold by Sumitomo, a large Japanese company. Japan is the only country in the world that produces nimetazepam. Outside Japan, Erimin is available in most of East and Southeast Asia and is widely used as a short-term treatment for people with severe insomnia who find it difficult to fall asleep or stay asleep. Sumitomo has stopped making Erimin since November 2015. It is still available as a generic or Lavol.

Nimetazepam was widely prescribed in the 1980s and 1990s, particularly in Japan, Malaysia, Brunei, the Philippines, Thailand, Indonesia, Hong Kong and Singapore. With abuse and addiction rampant, prescriptions for the drug have fallen sharply since 2005. It is used primarily as an anticonvulsant in children. It is also still used in the most severe and debilitating cases of insomnia in inpatient Settings or short-term outpatient treatment. For this purpose, the sleeping pills benzodiazepines Esazolam and nitrazepam were used more frequently than nitrazepam. Antidepressants such as trazodone and mirtazapine or Zopiclone and zolpidem are the first line drugs for insomnia.

Although the prescription of nimetazepam has decreased, abuse of the drug remains high in Brunei, Singapore, Malaysia and the Philippines. It is commonly used in combination with methamphetamine and ecstasy, as well as opioids (especially heroin or morphine). Nimetazepam is subject to strict legal restrictions in Malaysia, which have made the drug scarce, but many of the pills sold on the black market under the name Nimetazepam are counterfeit. Diazepam and nitrazepam are among the most commonly used benzodiazepines in the region, and as such, they are commonly diverted and sold on the black market, often as nitrazepam.

The illegal manufacture of Nimezepam (sold as Erimin-5) is widespread in the region. The abuse of nimetazepam continued to increase throughout the 2010s. Seizures of illicitly manufactured Erimin-5 tablets coincided with methamphetamine seizures in Malaysia. A small number of 46 illegal Erimin-5 tablets seized were tested for their physical and chemical properties. The active ingredient, dopant, primary diluent, and dye constitute the chemical characteristics of the tablet. The results showed that Nimetazepam was the most common active ingredient in the vast majority of seized tablets. Lactose was detected as the main diluent in most samples, followed by mannitol and then dicalcium phosphate dihydrate. Sunset yellow was found in most pill samples, used alone or in combination with other dyes (e.g. tartar and Lichenol 4R) to give the pill a peach/orange color. The green tablets in the sample contained bright blue and tartar dyes. Diazepam is primarily an anti-anxiety drug and is the active ingredient in only one of the 46 tablets. Nitrazepam, a powerful sedative and hypnotic and the parent drug of nitrazepam, was found to be a secondary compound, with caffeine being the main component combined in three tablets.

In 2003, Singapore seized 94,200 Erimin-5 tablets. The laboratory of the Central Narcotics Board (CNB) carried out tests on the tablets and the results confirmed that they were indeed nitrazepam.