New opioids are sold as substances in their own right and as replacements for controlled opioids. They are also mis-sold as or used to adulterate heroin and other controlled opioids for unsuspecting consumers. In some cases, they are used to make fake tablets of opioid analgesic medicines, such as oxycodone. Recent signs of the emergence in Europe of mixtures of benzodiazepines and xylazine with new opioids – seemingly copied from North America – also raise concerns. Occasionally, new opioids are found in non-opioid controlled drugs, such as cocaine.

New opioids are typically found as powders and, to a lesser degree, tablets and capsules. Other physical forms, such as liquids, are also reported but are far less common. Most use of new opioids is by high-risk drug users, including those who inject heroin and other opioids. A smaller number of people use them recreationally. In the latter case, this includes substances such as tramadol.

New opioids play a relatively small role in the drug market in most parts of Europe. However, many are highly potent and are a particular concern for public health because of the high risk of life-threatening poisoning from respiratory depression. Timely use of the antidote naloxone and supportive care are essential to treat overdoses.

While new opioids started to appear on the NPS market 15 years ago, since then they have been identified more often in some countries and may become more widespread in Europe. Related to this, while sporadic, cases of new opioids mis-sold as or used to adulterate heroin and other established opioids may be increasing. The use of synthetic opioids increases the risk of life-threatening poisoning for consumers, and can manifest as outbreaks that occur without warning.

In most cases, changes in the opioid market are driven by supply-side factors. Important factors leading to the use of new opioids include ease of production, lower price, higher potency, ease of transportation and smuggling compared with established opioids, and perhaps especially because the production of heroin is both labour- and time-intensive and reliant on many other factors (Zagorski et al., 2020). In addition, as many new opioids are not controlled under drug legislation, they can be manufactured, sold and transported relatively freely. In some cases, the use of new opioids may be a temporary response to reduced supply or increased costs of heroin and other established opioids.