Recent reports indicate that although the number of overdose fatalities in Canada is on the decline, a troubling new trend is emerging: medetomidine, a potent veterinary sedative, is increasingly being detected in the unregulated drug market. This alarming shift poses significant risks to users and healthcare systems already strained by the ongoing opioid crisis.
The Emergence of Medetomidine
Medetomidine is a powerful tranquiliser traditionally used by veterinarians. Dr. Emily Austin, medical director of the Ontario Poison Centre, has expressed concern that this drug has begun appearing in the illicit drug supply, which is particularly alarming as it is not approved for human use. A recent alert from the British Columbia Centre for Disease Control (BCCDC) highlights that medetomidine is often being mixed with opioids like fentanyl.
In Toronto, preliminary data from Drug Check Services suggests that up to 80 per cent of tested illicit drugs may contain medetomidine, surpassing the 50 per cent rate reported by public health authorities in British Columbia. Dr. Karen McDonald from the same service noted that the presence of this sedative has been linked to severe side effects, including hallucinations and dangerously low blood pressure.
A Spike in Veterinary Tranquilisers
The rise of medetomidine is not an isolated incident. In late 2023, there was a noticeable uptick in the detection of veterinary tranquillizers in fentanyl samples, with figures leaping from under 20 per cent prior to October 2023 to nearly 40 per cent by April 2024. In the most recent tests, this figure skyrocketed to an alarming 86 per cent.
Dr. Mark Lysyshyn, deputy public health officer at Vancouver Coastal Health, compared the current situation with medetomidine to previous instances of xylazine—another sedative that had been detected in the opioid supply. He noted that while xylazine contamination never exceeded five per cent, medetomidine’s prevalence is now contaminating 30 to 50 per cent of opioids in circulation.
The Impact on Overdose Rates
Despite the increase in the presence of these tranquilizers, B.C. has reported a decline in overdose deaths. From January to June 2025, the rate of apparent opioid toxicity deaths stood at 13.5 per 100,000 residents, down from a peak of 20 per 100,000 in 2023. This is a positive trend; however, the number of non-fatal overdoses is on the rise.
In Toronto, emergency services attended to 350 non-fatal and 12 fatal calls for suspected opioid overdoses, reflecting a stark increase from the monthly average of 229 non-fatal calls in early 2025. While the number of fatal overdoses remained steady at 12, this does not diminish the growing concern around the dangers posed by mixing opioids with sedatives that do not respond to naloxone, the standard overdose reversal drug.
Addressing the Crisis
Authorities are urging those involved in drug use to remain vigilant. The BCCDC’s recent alert emphasises the importance of calling 911 in the event of an overdose, highlighting that such incidents are medical emergencies. While naloxone may not effectively counteract the effects of non-opioid tranquilizers like medetomidine, it can still be crucial in situations where opioids are present.
Dr. Austin reassured that although the interaction of these substances complicates overdose management, administering naloxone can still restore respiratory function in cases involving opioids.
Why it Matters
The growing presence of medetomidine and other veterinary tranquilizers in Canada’s drug supply underscores the evolving and increasingly dangerous landscape of substance use. As healthcare professionals grapple with the complexities introduced by these new substances, the need for comprehensive strategies to address both overdose prevention and the underlying issues driving drug use becomes ever more critical. The ongoing decline in overdose deaths is a beacon of hope, but it must be paired with proactive measures to safeguard those at risk from the myriad dangers posed by this shifting drug landscape.
