Xylazine/’Tranq’ confirmed locally

Advisory Alert

February 21, 2023

*Cette information est seulement disponible en anglais.

To: Local Health System Partners


What is xylazine?

Xylazine (or ‘Tranq’) is a non-opioid tranquilizer designed for veterinary use on large animals that has muscle relaxant, anesthetic, sedative, and analgesic properties. It is not intended or approved for use in humans. Xylazine is a phenothiazine similar in action to clonidine and tizanidine and acts as an agonist on central alpha-2-adrenergic receptors. The effects of xylazine on the brain stem cause a rapid decrease in the release of both dopamine and norepinephrine. Effects of xylazine last much longer than fentanyl with a reported duration of 8 to 72 hours.

On February 15, 2023, Public Health Sudbury & Districts issued a Drug Alert following xylazine being confirmed locally. Xylazine has now been found locally and spanning across several provinces in Canada, including Ontario, as well as in the United States. The presence of xylazine as a cutting agent in both opioids and stimulants is increasing in popularity within the unregulated drug market. Xylazine is a cost effective and accessible compound that has been said to increase or prolong the effects of fentanyl. It is also used as a drug of choice when combined with other drugs. Routes of consumption include intravenous, intramuscular, subcutaneous, oral, snorting, and inhalation.

Recent data from the Toronto Drug Checking Service shows that around 18 to 20% of samples tested thus far in 2023 contained xylazine. The Office of the Chief Coroner for Ontario has also reported numerous drug-related deaths where xylazine was detected provincially, including in our district.

Adverse effects

Acute harms associated with xylazine include:

When xylazine is mixed with other opioids, benzodiazepines, stimulants and/or alcohol the risk for overdose greatly increases due to significant respiratory depression. Additionally, with symptoms akin to opioid toxicity, it can be difficult to distinguish between opioid and xylazine toxicity. Although naloxone will not work to reverse the effects of xylazine as a non-opioid, it is recommended that you administer naloxone as it will counteract the effects of any opioid consumed. There is currently no known antidote for xylazine.

Other harms

There have also been reports of delayed bradycardia and hypotension 1 to 2 days after use. Another harm associated with xylazine is severe, widespread necrotic skin lesions associated with repeated exposure. These lesions may even appear in areas where clients are not injecting and typically consist of multiple tunnelled abscesses with deep pockets and undermining. This disease process is related to the agonist effect xylazine has on alpha-1 adrenergic receptors causing local arterial vasoconstriction leading to insufficient tissue perfusion and subsequent necrosis.


The following resources may be useful in your own learning or in educating your colleagues and patients:


Original Signed By

Dr. Penny Sutcliffe
Medical Officer of Health and Chief Executive Officer

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This item was last modified on February 21, 2023