Rising threat of nitazenes joins fentanyl in Canada's toxic drug supply

The toxic drug crisis has taken more than 47,000 lives in Canada since 2016 and the synthetic opioid fentanyl has become a household name. But now, what's believed to be an even more potent class of synthetic drugs is showing up in drug busts across the country: nitazenes.

RCMP in Metro Vancouver, Labrador, and Prince Edward Island have seized nitazenes as part of drug busts this year.

Public health units in Ottawa and Quebec's Eastern Townships have also flagged them.

Here are some answers to common questions about the class of substances.

What are nitazenes?

Nitazenes are potent, synthetic opioids linked to overdose deaths in many parts of the world, according to the United Nations Office on Drugs and Crime.

Are they new?

No. Nitazenes were created aspotential pain relieversin the 1950s.

But they were never approved for clinical use, such as human or veterinary medicines, according to the U.K. Advisory Council on the Misuse of Drugs.

Since 2019, nitazenes have emerged within recreational drug supplies in the United States, Canada and European countries.

In a letter published by The Lancet Psychiatry in 2022, researchers based in Vancouver and Basel, Switzerland, said ultrapotent synthetic substances such as nitazenes are being rapidly produced in what were calledhomegrown laboratories using legal and easily available ingredients known as precursors.

Why are they so potent?

Nitazenes are often described as several times more potent than fentanyl, though there's no official estimate. While the potency and street appeal of the recreational drugs are similar, to chemists the structures differ.

Scientists have relatively little information about how the human body reacts to nitazenes because the chemicals have never gone through clinical trials that offer a chance to find out.

What are the possible harms?

Nitazenes can increase the risk of accidental overdose, especially when combined with other substances that suppress breathing and heart rate such as other opioids or benzodiazepines, the 2022 alert from the Canadian Centre on Substance Use and Addiction said.

The potency means symptoms can develop quickly before a person gets medical care. One type, isotonitazene, has been implicated in at least 200 deaths in Europe and North America. It was also the most frequently detected nitazene in Canada, a 2022 Health Canada report said.

The toxic effects of nitazene resemble those of morphine and fentanyl such as pinpoint pupils and slow or shallow breathing that can lead to death. People may also experience nausea and vomiting, be very pale and have low blood pressure or decreased heart rate.

Are there ways to check for it?

Not easily.

The Canadian Centre on Substance Use and Addiction's alert says fentanyl test strips cannot detect nitazenes, and detection of nitazenes by point-of-service drug checking requires sensitive equipment that is not always available.

Does naloxone work against it?

Naloxone is a medication that can temporarily reverse the effects of an opioid overdose, but it is not a cure, public health officials say.

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If anyone suspects or witnesses a person experiencing a drug overdose, call 911 and administer naloxone, even if the drug consumed is unknown. Being able to recognize the signs of an overdose quickly and having a naloxone kit can save a life, Ottawa Public Health (OPH) notes.

Because nitazenes are estimated to be several times more toxic than fentanyl, Benjamin Leikin, manager of community health and wellness at OPH, said the risk of overdose is increased. An individual experiencing an overdose may need greater than normal dose of naloxone.

An Australian-based group notes the effects of synthetic opioids typically last longer than naloxone, so the overdose may return after the naloxone has worn off. That's why it's important to get medical attention even if you have already administered naloxone.