High-potency additives to opioids making response, treatment by community workers difficult

In the midst of a city-wide overdose crisis, an alarming form of animal tranquillizer is now being found in Toronto’s street drug supply, making it increasingly difficult for community workers to combat this new threat.

According to Toronto’s Drug Checking Service, 81 per cent of expected fentanyl samples collected between December 13 and 26 contained a very potent veterinary tranquillizer. 

“We’ve seen two different veterinary tranquillizers present in Toronto’s unregulated drug supply, Xylazine, but more recently a drug called Medetomidine, which started presenting in December of 2023 but really didn’t take off until the fall of 2024,” Hayley Thompson, the managing director of Toronto’s Drug Checking Service, tells The Leader Spirit.

Experts say the additive Medetomidine – used regularly by veterinarians for animal sedation during surgery – is 200 times stronger than Xylazine and in humans can cause deep sleepiness, a slow heart rate and low blood pressure.

“We were seeing some of that with Xylazine, but it’s seeming from my experience and from what we see in the literature, that perhaps Medetomidine is causing more hypotension or low blood pressure and lower heart rates,” said Dr. Jessica Kent-Rice, an emergency medicine physician at St. Michael’s Hospital.

Toronto’s drug checking service reports that Medetomidine is currently found in three of every four fentanyl samples checked, compared to 2019, when benzodiazepines were most prevalent, mixed with opioids.

“The difference now that we’re seeing, though, is that while giving someone naloxone will help them breathe better, which saves their life, they won’t wake up as much as they used to in the past,” explains Kent-Rice.

Thompson says it has become very challenging for the community and existing supervised consumption sites to respond to these types of overdoses.

“They are set up to deal with respiratory issues, not heart issues, so some folks think that’s why we’re seeing a contribution or an increase in the number of ambulance calls that Toronto paramedics services is seeing.”

In the most recent data from Toronto Public Health, Toronto paramedics responded to an increased number of suspected opioid overdose-related calls from December 20 to 28, up 35 per cent compared to around the same time-period in the last two years.

“What would be optimal in this situation is if we see some type of stability brought to the fentanyl supply, whether that be through pharmaceutical alternatives being provided that actually meet people’s needs.”

Toronto’s drug checking service is calling for funding from the provincial government to expand the drug checking program, and to work collaboratively with all provincial partners to utilize their data, especially since the province has removed almost half of the city’s supervised consumption sites.

“Without supervised consumption sites and these hubs of community that people had, we are seeing more people use outside,” said Thompson. “I think it’s a time for compassion, for understanding, for education and not a time for divisive quarrelling.”

While there are no reversal agents for drugs like Medetomidine and Xylazine, experts say that if there is a suspected opioid overdose, naloxone is still the best medication to use in that scenario.