A deadly new class of synthetic opioids has been identified in cities throughout the United States at a time when fatal drug overdose rates are soaring.

Forensic scientists have identified nitazenes on streets throughout the country. The nitazene class has proven even stronger than fentanyl, the synthetic opioid the extreme potency of which is responsible for the majority of deadly overdoses in the U.S.

“There's probably about five to 10 drugs that make up this medicine class right now that have been identified on the market,” said Alex Krotulski, an expert in nitazenes at the Center for Forensic Science. “They're really spread through all areas throughout the U.S. Usually, we see them epicentered around places in the Midwest and then, they sort of proliferate out from there.”


The most commonly found drugs within the nitazene class are isotonitazene, metonitazene, and protonitazene, which have been found in many states such as Texas, Ohio, Indiana, New York, and New Jersey. Experts estimate the potency of the nitazene class to range from twice to 10 times as fatal as fentanyl, which is sometimes undetectably laced in heroin or cocaine and can be fatal in even miniscule doses.

“The majority of these nitazene analogs are more potent than fentanyl, especially the ones that we see. I think that's probably by design,” Krotulski said. “You've got drugs that are, say, one to two times more potent than fentanyl, that are two to three times more potent, and now you've got drugs that are 10 times more potent than fentanyl.”

The onset of the pandemic in Spring 2020 brought with it mandatory quarantines and social distancing, conditions that facilitated skyrocketing drug overdoses. The Centers for Disease Control and Prevention reported in July that fatal drug overdoses in 2020 increased by nearly 30% over the previous year, reaching an all-time high of more than 93,300. Opioids were the cause of a majority of overdose deaths in every state as well as D.C. Fatal overdoses caused by opioids specifically increased from 50,963 in 2019 to an estimated 69,710 in 2020.

Fentanyl and other synthetic opioids were involved in more than 60% of all fatal drug overdoses in 2020. Drug users who misuse nitazenes will often use them in concert with another substance, sometimes unknowingly. Drugs such as heroin or cocaine are often laced with trace amounts of extremely potent synthetic opioids to make them cheaper to traffic.

"Nowadays with the overdose epidemic, we're seeing a lot more poly drug use so you have to examine the drugs by themselves ... Then you also have to take into account the fact that these drugs are being found and used with fentanyl. And when you get into that scenario, you're just adding things together, adding potent on top of potent," Krotulski said.

Versions of fentanyl that have been chemically altered to be more potent, also called fentanyl analogs, have increased in popularity in recent years due to the government’s whack-a-mole-like approach to regulating the synthetic drugs. Since 2018, all fentanyl analogs have been categorized as schedule 1 substances, meaning they have extremely high abuse potential and no medical benefit.

When a drug is scheduled with the Drug Enforcement Administration and becomes harder to find, a newer drug takes its place. Enter: nitazenes.

“We're seeing the same thing happen where with fentanyl analogs, one drug would be prevalent, it would be scheduled by the DEA, that drug would go away, and then a new drug would be introduced into the market,” Krotulski said. “So, we're seeing this sort of cyclic pattern, if you will, of one drug after another after another after another.”

The synthetic opioids have also been identified in the District of Columbia, where opioid overdose deaths in the 12 months leading up to May 2021 reached about 498. D.C. ranks second behind West Virginia in the number of deaths due to opioid overdoses during the pandemic, according to an analysis from the Washington Post. Alexandra Evans, a chemist at the D.C. Public Health Lab was the first in the district to identify the drugs after finding residue on a used needle collected from the city’s needle exchange locations for intravenous drug users to discard used paraphernalia and get new supplies.

“We knew that it was a new type of synthetic opioid very quickly, based on its instrumental analysis report,” Evans said. “Our lab had heard about the discovery of nitazenes in other cities beginning in 2019. We were familiar with this drug class, and the specific drugs within it.”


The stress of COVID-19 and social isolation have contributed to the roughly 4 in 10 adults in the U.S. who have experienced increased rates of anxiety and depression, according to the Kaiser Family Foundation. Stay-at-home orders during the first wave of COVID-19 also made visiting with or checking in on people suffering with substance use disorders difficult and sometimes impossible.

COVID-19 has been difficult to track, and surges have been difficult to predict. The recent discovery of the omicron variant has concerned public health experts and healthcare workers who are still reeling from roughly 20 months of overcrowded ICUs and strained supplies. While the Biden administration has not indicated it will revert back to early pandemic restrictions such as business closures or stay-at-home orders, the U.S. will continue to beat back renewed surges into next year.