Recent data indicates a decline in overdose deaths across Canada, yet a troubling trend has emerged: the increasing presence of an animal sedative, medetomidine, within the unregulated drug market. This potent tranquiliser, primarily utilised by veterinarians, is now being mixed with opioids like fentanyl, raising significant alarm among health officials and advocates.
Medetomidine: A New Threat in the Drug Supply
The B.C. Centre for Disease Control has recently issued a warning regarding the alarming rise of medetomidine in the illicit drug landscape. Dr. Emily Austin, medical director of the Ontario Poison Centre, highlighted the issue, stating, “Medetomidine itself is used by veterinarians, and we don’t have approval to be using that in humans. We’ve started to see it showing up in the unregulated drug supply.”
Toronto’s Drug Check Services suggest that approximately 80 per cent of illicit drugs are now tainted with this tranquiliser, surpassing the 50 per cent reported by public health officials in British Columbia. This stark rise reflects a worrying trend that could have dire implications for public health.
Health Risks Associated with Medetomidine
The side effects associated with medetomidine are concerning, including potential hallucinations, dangerously low blood pressure, and bradycardia, or slow heart rates. Dr. Karen McDonald from Toronto’s Drug Check Services noted that the first detection of medetomidine in fentanyl samples occurred in December 2023. Since then, there has been a dramatic increase in its prevalence. Previously, the proportion of fentanyl samples containing medetomidine was below 20 per cent; however, by April 2024, this figure surged to nearly 40 per cent, and it reached an alarming 86 per cent last month.
This escalation is significant when compared to xylazine, another animal tranquiliser that has previously been found in fentanyl. Dr. Mark Lysyshyn, deputy public health officer at Vancouver Coastal Health, explained that xylazine never contaminated more than five per cent of opioids in B.C. “Medetomidine, right now, is contaminating 30, 40, 50 per cent of opioids,” he stated, underscoring the severity of the situation.
The Broader Implications for Public Health
The addition of sedatives like medetomidine to opioids is part of a troubling trend that has been developing since 2019 when benzodiazepines began appearing in the drug supply. Dr. Lysyshyn suggested that this practice likely aims to amplify the effects of opioids. He noted a surge in overdose events, including an uptick in 911 calls and emergency room admissions.
Interestingly, despite the increase in emergency visits, the rate of overdose deaths in B.C. continues to decline. “Although it’s causing major problems for people who use drugs and major problems for the health-care system right now, it’s not increasing the risk of death,” Lysyshyn remarked. Statistics from the federal government’s Health Infobase reveal that the rate of apparent opioid toxicity deaths from January to June 2025 was 13.5 per 100,000 Canadians, a significant drop from the peak of 20 per 100,000 during the opioid crisis in 2023.
Non-Fatal Overdoses on the Rise
While the overall death rate may be falling, non-fatal overdoses are becoming increasingly prevalent. In Toronto, paramedics responded to 350 non-fatal and 12 fatal calls related to suspected opioid overdoses, surpassing the monthly average of 229 non-fatal calls in 2025. Though the fatal overdose figures remained steady, the rise in non-fatal incidents signals a pressing issue.
It is unclear how many of these overdose cases involved veterinary tranquilizers, but experts like Dr. McDonald warn that these substances pose heightened risks. “The combination of drugs like medetomidine and xylazine in combination with fentanyl do increase risks for people using those drugs,” she stated. Notably, these tranquilizers do not respond to naloxone, the standard treatment for opioid overdoses, complicating the situation further.
In response, the B.C. Centre for Disease Control has urged individuals to call 911 immediately if they suspect an overdose, emphasising that drug poisonings are medical emergencies. Although the presence of tranquilizers complicates overdose management, officials recommend that naloxone should still be administered during an overdose situation, as it can restore breathing in cases involving fentanyl.
Why it Matters
The emergence of medetomidine and other veterinary tranquilizers in the unregulated drug supply highlights a critical public health challenge. As Canada grapples with the ongoing opioid crisis, the introduction of these potent sedatives adds a layer of complexity that could exacerbate the risks faced by individuals who use drugs. Ensuring that healthcare systems are equipped to respond effectively to this evolving landscape is essential for safeguarding the health of Canadians and reducing the burden on emergency services. The urgency of addressing this issue cannot be overstated, as it impacts not only individuals but also the broader community and healthcare infrastructure.
