Editorial: The challenge posed by new synthetic opioids: pharmacology and toxicology

Diverted prescription opioid analgesics (e.g., oxycodone, hydrocodone, hydromorphone), failed opioid drug candidates (e.g., benzamide derivatives), and various legal and illegal fentanyl analogs (e.g., acetyl fentanyl, furanylfentanyl, carfentanil) constitute the class of New Synthetic Opioids (NSOs), which is currently posing a global public health threat (Pichini et al., 2018). Due to the low cost of materials and equipment required for clandestine laboratory production and enormous profit potential, NSOs are establishing a strong position on the illegal drug market as stand-alone products, adulterants in heroin, or constituents of counterfeit prescription medications. Recently, NSOs have been involved in a significant spike of acute intoxications (classic opioid toxidrome) and overdose deaths in North America, challenging healthcare professionals, law enforcement agencies fighting against their diffusion, and policymakers trying to restrain their use (Marchei et al., 2018; Busardò et al., 2019). Since there is little information available regarding the pharmacology and the toxicology of NSOs in abuse settings, the main purpose of this Research Topic was to fill the current knowledge gap. The topic covers basic scientific, epidemiological, and clinical aspects of NSOs and includes 3 reviews, 3 mini-reviews, 1 original article, 2 case reports, and 1 opinion.