US and European authorities are battling a new enemy in the war against opioids. Nitazenes are a class of synthetic drugs 40 times more potent than fentanyl that have caused hundreds of confirmed deaths across Europe and the US since appearing on the radar of law enforcement agencies in 2019. However, this figure is likely to be a significant undercount.
Nitazenes were first synthesized in the 1950s by CIBA Aktiengesellschaft, an Austrian chemical company, which created several chemically related molecules with different levels of pain-killing potency. However, their use as painkillers never took off. As well as being highly addictive, nitazenes can cause respiratory depression, a dangerous condition where breathing becomes too shallow to replenish oxygen in the blood. These drugs were therefore largely unheard of for decades until they appeared in the illegal market.
It’s difficult to say exactly when nitazenes started being commonly sold as street drugs—identifying them requires specific tests that are not routinely performed—but law enforcement agencies started noticing them about six years ago. A shipment of one type of these synthesized molecules—isotonitazene—was intercepted in the US Midwest in 2019, and deaths started being reported in both the US and Europe over the following years.
Drugmakers and dealers were likely attracted to nitazenes because of their potency and because they have similar effects to better-known drugs such as heroin. This makes them useful substances to dealers, as they can use them to cut other opioids to make their drugs go further, increasing the volume that they can sell. This poses serious risks to users, who are often unaware of what they are actually taking, raising the threat of overdosing.
The other attractive characteristic of nitazenes was that they had been forgotten about by authorities: A drug that has less attention on it, as well as an ill-defined legal status, is easier to trade. Illegal laboratories are believed to have begun synthesizing nitazenes using historical chemical formulas found in pharmacology textbooks as well as developing new formulas.
In the US, nitazenes are now widespread throughout most of the country and are manufactured in Mexico or within the country in illegal laboratories supplied with raw materials by Asian dealers. Synthetic opioids are the most problematic drug in the US—accounting for roughly 70 percent of the 105,000 overdose deaths recorded in 2023—and of these, fentanyl is the most prevalent. But nitazenes, while still a minority drug, are quickly becoming more common.
Europe, for its part, has always been a market dominated by heroin, with almost all of this coming from Afghanistan. However, when the Taliban regained power in Afghanistan in 2021, it banned cultivation of the opium poppy, and so cut off the source of the raw material used to create heroin destined for Europe. As stockpiles of opium run out, it is possible that there will be a shortage of heroin in the European market that synthetic opioids could fill.