Dangerous veterinary tranquilizers now found in most fentanyl samples

Fentanyl is often laced with animal tranquilizers, but without consistent testing or surveillance, officials are flying blind

Clareview bus station in Edmonton, Alberta; July 2024. | Courtesy of George Cherry/Facebook

By Alexandra Keeler | 4-minute read

In March, more than three-quarters of Toronto fentanyl samples tested by the city’s drug checking service were tainted with veterinary tranquilizers — commonly known as “tranq.”

“This is a huge increase,” said Karen McDonald, lead of Toronto’s Drug Checking Service.

The permitted purpose of these tranquilizers is to sedate large animals. But since 2019, these drugs — primarily xylazine and medetomidine — have increasingly been mixed in with fentanyl to extend its effects.

Xylazine has been dubbed the “zombie drug” for its heavy sedative effects and its link to slow-healing, painful skin ulcers that can, in extreme cases, lead to limb loss.

Medetomidine is even more potent in its sedative and pain-relieving effects, increasing the risk of overdose.

“The level of contamination of the unregulated fentanyl supply and [its unpredictability] make it near impossible for those who use it to be able to minimize harms,” said McDonald.

Yet, despite the prevalence of tranq in fentanyl, Canada continues to rely on a patchwork of community data and outdated surveillance — leaving policymakers flying blind.

The tranq crisis

Xylazine was first identified in drug samples in Canada as far back as 2001; medetomidine, in 2023.

In early 2024, the tranquilizers started to become prevalent in Ontario and Quebec’s drug supply. More recently, it has been identified in B.C.’s drug supply as well.

“We don’t know much about the short- or long-term effects of exposure to them,” Raadiya Malam and Samantha King, research and policy analysts at the Canadian Centre on Substance Use and Addiction, told Canadian Affairs in an email.

Tranq is most often found in drugs marketed as fentanyl, says McDonald. “The vast majority of people exposed to these drugs are not aware they are consuming them,” she said.

Because tranquilizers are not opioids, naloxone — the standard opioid overdose reversal medication — does not work on them.

As a result, harm reduction and health-care workers are adapting their strategies. They are focusing on wound care, updating overdose and withdrawal protocols, and extending post-naloxone monitoring, Malam and King say.

Toronto’s paramedics do not track xylazine or medetomidine overdose cases. But they are trained to recognize the symptoms associated with overdose, including when multiple substances are involved, a spokesperson for Toronto Paramedic Services said.

Toronto police do warn the public about toxic drug trends. But their primary mandate is to investigate and target substances prohibited under the Controlled Drugs and Substances Act. Xylazine and medetomidine are not classified as prohibited substances under this act.

Rather, the tranquilizers are regulated for use by licensed veterinarians.

Lori Ahronson, a spokesperson for the Canadian Veterinary Medical Association, says the association is concerned that efforts to restrict xylazine and medetomidine could negatively impact animal care. “They are essential to prevent and treat pain and suffering in animals,” she said.

In the U.S., xylazine is also federally regulated as a veterinary drug. But in 2023, some states introduced import restrictions as a response to the drug crisis. Some states have also classified it as a controlled substance to better empower law enforcement to crack down on its illicit use.

At the federal level, the U.S. Drug Enforcement Administration supports a recently reintroduced bill to classify xylazine as a Schedule III controlled substance. The American Veterinary Medical Association has endorsed the bill, which includes exemptions for licensed veterinarians, saying it would curb illicit use while preserving access for animal care.

Canadian Affairs asked Health Canada whether it would consider taking a similar approach in Canada. A Health Canada spokesperson said the agency is working with law enforcement and the veterinary community to prevent illegal xylazine imports.

Due to limited tracking and their status outside the Controlled Drugs and Substances Act, both xylazine and medetomidine are difficult to monitor, and their supply routes remain unclear.

Flying blind

The true toll of xylazine and medetomidine in overdose deaths remains unknown.

Canada’s main drug surveillance system, the Canadian Drug and Substance Watch, is meant to flag emerging threats through police submissions, wastewater analysis and web scraping. As of its most recent update in November, the database tracked 1,678 substances, but xylazine and medetomidine were not among them.

At the provincial level, the Office of the Chief Coroner of Ontario only recently began systematically detecting tranquilizers in opioid-related deaths, according to Stephanie Rea, issues manager at the office.

So far, xylazine and medetomidine have been detected in only a small number of confirmed opioid toxicity deaths. But these deaths exclude many drug-related fatalities, such as deaths involving multiple substances where opioids are not the primary cause.

Ontario’s public health agency has its own drug surveillance tool that provides data on drug-related deaths. However, it does not offer information on tranquilizers such as xylazine or medetomidine.

Toronto does not track deaths or overdoses involving fentanyl mixed with xylazine or medetomidine, a Toronto Public Health spokesperson said.

The spokesperson noted that Toronto Public Health often lacks verified information about the specific drugs involved in overdoses, and relies on data from Toronto’s Drug Checking Service.

Canary in the coal mine

Toronto’s Drug Checking Service is a sort of canary in the coal mine — offering real-time, community-level warnings about the unregulated drug supply.

Based at St. Michael’s Hospital in downtown Toronto, the free, anonymous drug checking program allows individuals to submit small amounts of their substances for testing. The service provides users with detailed information about the contents of the substance, which are also published in public, bi-weekly reports.

The service was the first in Canada to publicly report xylazine in September 2020 and medetomidine in December 2023.

“Drug checking services and community-led unregulated drug market monitoring … are critical in identifying and educating on new/novel drugs and drug market trends,” said McDonald, lead of Toronto’s Drug Checking Service.

“They provide the only source of real-time and public information on the unregulated drug supply in the country.”

In March, 77 per cent of fentanyl samples submitted to the service contained veterinary tranquilizers, mostly xylazine.

“We would not have this data about xylazine or medetomidine if people who use drugs did not donate their drugs to our program in an effort to reduce the harms associated with [them],” said McDonald.

Various provincial health, police and coroner organizations use the service’s data.

Despite its importance, the service is at risk. Two of its collection sites — Regent Park Community Health Centre and The Works — closed their services on April 1 after Ontario shuttered supervised consumption sites near schools and daycares.

The province is instead directing funding to new Homelessness and Addiction Recovery Treatment (HART) Hubs, which provide primary and addiction care but exclude harm reduction services such as needle exchanges or drug checking.

“Our program currently has federal funding […] until June of 2025,” said McDonald. “After that time, we do not have a long-term funding commitment and will be forced to wind down services.”

Malam and King say they would like to see more timely and frequent updates to national surveillance systems.

“Access to these data will enable us to provide informed and flexible policy responses,” they said.

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This article was produced through the Breaking Needles Fellowship Program, which provided a grant to Canadian Affairs, a digital media outlet, to fund journalism exploring addiction and crime in Canada. Articles produced through the Fellowship are co-published by Break The Needle and Canadian Affairs.