title: Understanding the availability, prevalence of use, desired effects, acute toxicity and dependence potential of the novel opioid MT-45.
abstract: BACKGROUND
  1-Cyclohexyl-4-(1,2-diphenylethyl)piperazine (MT-45) is a novel psychoactive substance available over the Internet. MT-45 is an opioid-like compound. This study provides an overview of availability, use and desired and unwanted effects of MT-45 through triangulation of available data sources.
  
  
  METHODS
  Searches of the published scientific literature and 'grey' information sources, using the keywords 'MT 45', 'MT-45' and '1-cyclohexyl-4-(1,2-diphenylethyl)piperazine' were undertaken in June 2014 to identify information on the availability, prevalence of use and desired/unwanted effects of MT-45. In addition an Internet snapshot survey in English was undertaken in May 2014 to determine the availability and cost of MT-45.
  
  
  RESULTS
  In June 2014 we were unable to identify any studies reporting the prevalence of use of MT-45. The Internet snapshot study identified 17 Internet sites selling MT-45. Information on price was available from 9 sites, with the mean price of MT-45 decreased with increasing purchase amounts from US$57.60 ± 19.37 per gram for a 1-g purchase to US$3.36 ± 1.83 per gram for a 1-kg purchase. We identified one published scientific paper reporting on the acute harms in nine cases of analytically confirmed MT-45 toxicity, one US government report relating to two MT-45-related deaths and 20 user reports on Internet discussion forums relating to the use of MT-45. All these suggest that the desired and unwanted effects of MT-45 are similar to those seen with other opioids, and that the opioid-like unwanted effects may be reversed with the opioid antagonist naloxone. There were user reports of MT-45 being used in heroin withdrawal and of 'withdrawal symptoms' after use, suggesting that long-term use may be associated with dependency as seen with other opioids.
  
  
  CONCLUSIONS
  Combining published scientific literature and 'grey' information sources, we have demonstrated that MT-45 has opioid-like desired and unwanted effects. Whilst the information is limited at the moment, it has the potential to have similar dependence liability to other opioids.
authors.affiliation: General Medicine, Guy's and St Thomas' NHS Foundation Trust, and King's Health Partners , London , UK.
authors.forename: Sindhu
authors.initials: S
authors.lastname: Siddiqi
authors.forename: Charlotte
authors.initials: C
authors.lastname: Verney
authors.forename: Paul
authors.initials: P
authors.lastname: Dargan
authors.forename: David M
authors.initials: DM
authors.lastname: Wood
mesh_terms: D000701:Analgesics, Opioid / Q000633:toxicity*; D016208:Databases, Factual; D004305:Dose-Response Relationship, Drug; D006801:Humans; D010879:Piperazines / Q000633:toxicity*; D015995:Prevalence; D019966:Substance-Related Disorders / Q000175:diagnosis* / Q000453:epidemiology*
chemical_list: D000701:Analgesics, Opioid; D010879:Piperazines; C012631:(+,-)-1-cyclohexyl-4-(1,2-diphenylethyl)piperazine
keywords: MT-45; Novel psychoactive substance; Recreational drugs; Toxicity