Those watching Toronto’s drug supply say animal tranquilizers which cause flesh-eating wounds are turning up in street drugs with concerning frequency.

"We are seeing it fairly frequently," Ray Clark, a health promoter at Parkdale Queen West Community Health Centre, recently told CTV News Toronto.

The centre runs two safe consumption sites and oversees 1,100 client visits per month. They say more people are coming in with wounds caused by animal tranquilizers, or tranqs, that are being added to fentanyl.

One of the drugs, Xylazine, was first found in Toronto’s drug supply in Sept. 2020. Another, Medetomidine, first turned up in the city's drug supply in Dec. 2023.

Neither drug is approved for human consumption. Injecting them can cause wounds all over the body. 

"Our nurses are doing wound care once, twice, three times a day," Clark said. "If I'm injecting here, Xylazine-associated wounds could appear on my leg, on my torso, on my calf."

While naloxone can reverse the effects of fentanyl on a person experiencing an overdose, it cannot negate the dangerous effect of the tranquilizers, which are being added to the drugs.

Hayley Thompson with Toronto's Drug Checking Service says the levels of the tranquilizers in the drug supply also appear to be increasing.

"The potency of those drugs we’ve seen steadily increase," she said.

Her group works out of St. Michael's Hospital and regularly analyzes samples of street drugs in a lab. They first identified the tranquilizers in Toronto's supply.

"We’re now seeing particularly medetomidine in 20 to 30 percent of expected fentanyl samples and xylazine in around 10 (per cent)," Thompson said. "So that means that an animal tranquilizer of one kind or another is presenting in 30 to 40 per cent of expected fentanyl samples."

Data from the Office of the Chief Coroner of Ontario shows that while a similar number of opioid deaths occurred in 2020 (2,449) and 2023 (2,446), the number of deaths with xylazine present jumped from six to 75 respectively.

In addition to the wounds, medetomidine can also drastically slow one's heart and breathing.

"We’re seeing pulses in the low 30s and is some instances in the low 20s, where we’ve had to cut shirts off and attach automated external defibrillators device," Clark said.

He said more understanding and compassion are needed in the community to help tackle the crisis.

"The public needs to understand this is a public health crisis, these people are purchasing a substance that they expect to be fentanyl and they're getting a substance that is contaminated," Clark said.  Medetomidine is relatively more recent but I expect that because it has similar properties to xylazine we will see Medetomidine-related wounds as well."

Thompson said it's difficult to keep up with the ever-changing make-up of the drug supply and that better government policy is needed to tackle the opioid crisis.

"Whether that be we go the route of regulation like we have done with alcohol and cannabis, or whether we go to a medicalized model where safer supply has gone," better options are needed, she said.