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Concerns are mounting across Canada regarding the presence of medetomidine, a veterinary sedative, in the unregulated drug market, even as overdose deaths show signs of decline. This potent tranquiliser, primarily used by veterinarians, has been increasingly detected in illicit substances, particularly in combination with opioids such as fentanyl. Experts warn that this trend poses significant risks to users and healthcare systems alike.
Medetomidine: A Growing Threat
The British Columbia Centre for Disease Control recently issued a warning about the rising prevalence of medetomidine in the local drug supply. Dr. Emily Austin, the medical director of the Ontario Poison Centre, highlighted the alarming trend, stating, “Medetomidine itself is used by veterinarians, and we don’t have approval for human use. It’s now appearing in the unregulated drug supply.”
This veterinary tranquiliser has been identified in approximately 80 per cent of illicit drug samples analysed by Toronto’s Drug Check Services, significantly exceeding the 50 per cent detection rate noted by public health officials in British Columbia.
Dr. Karen McDonald from Toronto’s Drug Check Services elaborated on the risks associated with medetomidine, noting its potential side effects, which include hallucinations, dangerously low blood pressure, and bradycardia or slow heart rates. She reported that it was first detected in fentanyl samples in December 2023, with a notable increase in its presence in recent months.
A Shift in Drug Composition
The emergence of medetomidine is part of a broader trend in the drug supply, which has seen various substances being mixed with opioids. Previously, xylazine, another animal tranquiliser, was frequently found in fentanyl, known for causing severe skin lesions among users. Dr. Mark Lysyshyn, deputy public health officer at Vancouver Coastal Health, highlighted the stark contrast in the prevalence of these substances: “Xylazine never reached more than five per cent of opioids in B.C., whereas medetomidine is contaminating 30 to 50 per cent of opioids.”
The addition of such sedatives to opioids has been on the rise since 2019, when benzodiazepines began appearing in the drug supply, suggesting a troubling trend towards more potent and dangerous combinations. Dr. Lysyshyn indicated that this practice is likely motivated by the desire to enhance the effects of opioids, leading to an alarming increase in overdose incidents, including emergency room visits and 911 calls.
Overdose Trends: Death Rates Versus Non-Fatal Incidents
Despite the surge in non-fatal overdoses linked to these new drug combinations, the rate of overdose deaths in British Columbia continues to decline. Data from the federal government’s Health Infobase indicates that the apparent opioid toxicity death rate fell to 13.5 per 100,000 Canadians from January to June 2025, down from a peak of 20 per 100,000 during the height of the opioid crisis in 2023.
However, paramedic services in Toronto recorded an uptick in both non-fatal and fatal calls related to suspected opioid overdoses, indicating that while fatalities may be decreasing, the danger posed by these substances remains high. In January 2025, there were 350 non-fatal and 12 fatal overdose calls, compared to averages of 229 non-fatal calls earlier in the year.
Dr. McDonald noted that while the incidence of overdose deaths may not be increasing, the combination of medetomidine and xylazine with fentanyl creates additional risks for users, as these veterinary tranquilizers do not respond to naloxone, the standard overdose reversal drug.
Health Officials Urge Caution
In light of these developments, the BCCDC has urged individuals to call 911 without delay if they suspect someone is experiencing an overdose. They stress that drug poisonings are medical emergencies requiring immediate attention. While the presence of non-opioid substances complicates overdose responses, health officials maintain that naloxone should still be administered, as it can restore breathing in cases where fentanyl is also present.
Dr. Austin emphasised the complexities involved: “The effect that naloxone will have when somebody has used something that includes fentanyl along with medetomidine and xylazine is complicated, but it will restore that person’s ability to breathe if you give the right dose.”
Why it Matters
The increasing presence of veterinary tranquilizers like medetomidine in the drug supply underscores a critical public health crisis in Canada. As the landscape of substance use evolves, so too must our strategies for prevention and treatment. The dual challenge of addressing non-fatal overdoses while ensuring that fatality rates decline requires a multifaceted approach, including public education, improved access to emergency interventions, and robust support systems for those struggling with addiction. The evolving threat of these potent sedatives necessitates urgent action and dialogue among healthcare providers, policymakers, and the community to mitigate the risks and protect vulnerable populations.
