Why do illicit drugs have veterinary tranquilizers added and why is this dangerous?

Veterinary tranquilizer

Both Vancouver Coastal Health and the FNHA issued warnings about the drug supply being contaminated with medetomidine this week.

VCH said that there had been an increasing number of non-fatal overdoses in recent weeks linked to fentanyl being contaminated with the animal tranquilizer, which, like xylazine, does not respond to naloxone.

"Medetomidine overdose is like opioid overdose but also includes low heart rate and prolonged sedation (sedation for many hours)," the health authority said in a warning.

WATCH | Animal tranquilizer called xylazine also found in drugs:

More street drugs being laced with toxic animal tranquillizer

March 22, 2023|

Duration2:38

A dangerous animal tranquillizer called xylazine is increasingly finding its way into the illegal drug supply, Health Canada data shows. The drug can cause serious side effects and is resistant to naloxone, the fast-acting medication that can reverse opioid overdoses.

Officials urged drug users to get their drugs checked, and said naloxone should still be given out if an overdose is suspected.

Wieman said that medetomidine had been found intermittently in the unregulated supply since 2023.

See: B.C. sees record number of 911 calls about toxic drug overdoses, health authority says by Akshay Kulkarni · CBC News · Posted: Nov 27, 2025 7:00 AM PST