Illicit fentanyls in the opioid street market: desired or imposed?

BACKGROUND: Illicitly manufactured fentanyl and its analogues are appearing in countries throughout the world, often disguised as heroin or counterfeit prescription pills, with resulting high overdose mortality. Possible explanations for this phenomenon include reduced costs and risks to heroin suppliers, heroin shortages, user preferences for a strong, fast-acting opioid and the emergence of Dark Web cryptomarkets. This paper addresses these potential causes and asks three questions: (1) can users identify fentanyl; (2) do users desire fentanyl; and (3) if users want fentanyl, can they express this demand in a way that influences the supply? ARGUMENT/ANALYSIS: Existing evidence, while limited, suggests that some users can identify fentanyl, although not reliably, and some desire it, but because fentanyl is frequently marketed deceptively as other drugs, users lack information and choice to express demand effectively. Even when aware of fentanyl's presence, drug users may lack fentanyl-free alternatives. Cryptomarkets, while difficult to quantify, appear to offer buyers greater information and competition than offline markets. However, access barriers and patterns of fentanyl-related health consequences make cryptomarkets unlikely sources of user influence on the fentanyl supply. Market condition data indicate heroin supply shocks and shortages prior to the introduction of fentanyl in the United States and parts of Europe, but the much lower production cost of fentanyl compared with heroin may be a more significant factor CONCLUSION: Current evidence points to a supply-led addition of fentanyl to the drug market in response to heroin supply shocks and shortages, changing prescription opioid availability and/or reduced costs and risks to suppliers. Current drug users in affected regions of the United States, Canada and Europe appear largely to lack both concrete knowledge of fentanyl's presence in the drugs they buy and access to fentanyl-free alternatives.