Chapter16 - Novel synthetic opioids

Abstract

Novel synthetic opioids (NSOs), such as fentanyl, fentanyl derivatives and newly emerging analogues, have become increasingly available in the recreational drug market worldwide in recent years. Fentanyl is a synthetic phenylpiperidine with analgesic and anaesthetic properties. It is available as a stand-alone product, as an adulterant in heroin, cocaine and amphetamines or as a constituent of illicit prescription medications. In addition to fentanyl and the fentanyl analogues such as carfentanyl, acetylfentanyl, butyrylfentanyl and furanylfentanyl, numerous other potent NSOs have recently appeared on the illicit drug market; many of these have chemical structures that do not resemble morphine or fentanyl, however, they are active at the μ-opioid receptor. These novel synthetic opioids include the benzamide-based opioids U-47700 and AH-7921, tianeptine and MT-45. Novel synthetic opioids are amongst the most abundant and potentially lethal new psychoactive substance (NPS) chemical subclass. Currently, the true prevalence of use of NSOs is hard to determine as newer modified compounds that circumvent existing drug laws are being synthetized and introduced into the drug market on a regular basis. This necessitates the availability of reference material and rapid analytical method developments to keep track of these emerging opioids. Opioids, whether natural or synthetic, cause respiratory depression leading to acute hypoxia and hypercapnia through central nervous system depression. This chapter will focus on selected synthetic opioids including fentanyl, its NPS derivatives, and other common NSOs. The physical and chemical properties, pharmacology, toxicity and abuse potential of these synthetic opioids are discussed in this chapter.