Fentanyl is a synthetic μ-opioid receptor agonist approved to treat severe to moderate pain with faster onset of action and about 100 times more potent than morphine. Over last two decades, abuse of fentanyl and its derivatives has an increased trend, globally. Currently, the United States (US) faces the most serious situation related to fentanyl overdose, commonly referred to as the opioid epidemic. Nowadays, fentanyl is considered as the number one cause of death for adults aged 18-45 in the US. Synthesis and derivatization of fentanyl is inexpensive to manufacture and easily achievable. Indeed, more than 1400 fentanyl derivatives have been described in the scientific literature and patents. In addition, accessibility and efficacy of fentanyl and its derivatives can play a potential role in misuse of these compounds as a chemical weapon. In this review, the properties, general pharmacology, and overdose death cases associated with fentanyl and selected derivatives are presented. Moreover, current opioid epidemic in the US, Moscow theatre hostage crisis, and potential misuse of fentanyl and its derivatives as a chemical weapon are disclosed.

Biomedical Research Centre University Hospital in Hradec Kralove Sokolska 581 50005 Hradec Kralove Czech Republic

Department of Chemistry Faculty of Science University of Hradec Kralove 50003 Hradec Kralove Czech Republic

Doping Research Chair Zoology Department College of Science King Saud University Riyadh 11451 Kingdom of Saudi Arabia

Key Laboratory of Zoonosis of Liaoning Province College of Animal Science and Veterinary Medicine Shenyang Agricultural University Shenyang 110866 China

NBC Defence Institute University of Defence 68201 Vyskov Czech Republic

Philosophical Faculty University of Hradec Kralove 50003 Hradec Kralove Czech Republic

School of Food and Biological Engineering Hefei University of Technology Hefei 230009 China

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