Since late January, Toronto’s Drug Checking Service has observed a sharp increase in the number of fentanyl samples containing benzodiazepine-related drugs. While the combination of high-potency opioids and benzodiazepine-related drugs (i.e., benzo-dope) is not new, in February:
- Over 40% of fentanyl samples contained a benzodiazepine-related drug (we have not observed this degree of benzodiazepine contamination since October 2024)
- Almost all fentanyl samples containing a benzodiazepine-related drug also contained medetomidine (samples have more commonly contained one or the other)
Benzodiazepine-related drugs found in fentanyl samples checked since late January include ethylbromazolam, desalkylgidazepam, ethylflualprazolam, bromazolam, deschlorodemethyldiazepam, desmethylflutiazepam, flualprazolam, and nordiazepam. For most of these benzodiazepine-related drugs, very little is known about their strength or the duration of their effects, particularly when they are used in combination with other central nervous system and/or respiratory depressants.
In July 2025, we released What’s going on with benzo-dope in Toronto?, sharing that veterinary tranquilizers, particularly medetomidine, appeared to be replacing benzodiazepine-related drugs in Toronto’s unregulated fentanyl supply. Each month from May – December 2025, only 14% of fentanyl samples contained benzodiazepine-related drugs on average (compared to 67% that contained medetomidine).
Toronto’s volatile unregulated fentanyl supply appears to yet again be undergoing a notable shift. Using high-potency opioids, benzodiazepine-related drugs, and medetomidine – all of which are central nervous system and/or respiratory depressants – in combination:
- Increases the risk of harms, particularly overdose and extreme sedation
- Increases the risk of dangerous suppression of vitals, such as slowing down of breathing, blood pressure, heart rate
- Complicates overdose response
We are sharing this update as regions throughout Ontario, such as Toronto, Windsor-Essex, Chatham-Kent, and Sudbury, are reporting rising fatal and non-fatal overdoses. We suspect these increases may be associated with the growing presence of benzodiazepine-related drugs alongside medetomidine and high-potency opioids in the unregulated fentanyl supply. We are observing similar trends in fentanyl samples collected in other regions participating in our provincial public health and safety program, including Kingston and Peterborough.
If you suspect an opioid-related overdose involving medetomidine and/or benzodiazepine-related drugs, use naloxone and prioritize breathing. Naloxone alone may not make someone responsive if medetomidine and/or benzodiazepine-related drugs are contaminating their fentanyl.
We are continuing to monitor this trend and will keep the community informed as we learn more. To interact with our data, visit www.drugchecking.community.