The evolving potency of Canada’s unregulated opioid supply

• Over 10 years, the share of seized opioids with fentanyl or fentanyl analogues increased from 3% to 68%
• Health Canada tested drug seizure samples submitted by law enforcement from 2012 to 2022
• The findings demonstrate the increasing toxicity of Canada’s unregulated drug supply

Over the past decade, synthetic opioids like fentanyl and its analogues have been increasingly involved in overdose deaths in Canada. Fentanyl is about 100 times stronger than morphine, while carfentanil, though much less common, is roughly 100 times more potent than fentanyl. This study sought to understand trends in the presence of fentanyl, carfentanil and other fentanyl analogues over time and across regions in Canada. 

Study details

This exploratory cross-sectional study¹analyzed data from all opioid samples that were seized by Canadian law enforcement agencies and submitted to the Health Canada Drug Analysis Service (DAS) between 2012 and 2022. When law enforcement agencies seize illegal drugs they voluntarily submit the drug samples to the DAS, which uses internationally recognized drug testing methodologies to confirm the presence of illegal drugs. The study authors analyzed data from the samples over time and by province/region. The analyses combined data from the Atlantic provinces because of the small populations of those provinces and excluded data from the territories because of the low number of opioid samples from those jurisdictions. 

Results

There were 157,616 opioid samples submitted to the DAS from Canadian provinces over the 10-year period (2012–2022). Key findings from the analysis include the following:

• 51.5% (81,165) of all opioid-containing samples tested positive for fentanyl or a fentanyl analogue. Of these:
  • 94.5% (76,711) contained fentanyl 
  • 7.2% (5,380) contained carfentanil
  • 7.1% (5,744) contained a different fentanyl analogue
• The presence of fentanyl or fentanyl analogues inceased substantially over the study period, from 3.0% in 2012 to 68.3% in 2022. 

Provincial and regional trends 

British Columbia consistently had the highest proportions of fentanyl in its opioid samples. The fentanyl or fentanyl analogue positivity rates increased from 4.9% in 2012 to 21.3% in 2015, then rose dramatically up to 61.2% in 2016 and again to 91.2% in 2018. There was a slight decrease in 2022 down to 84.7%. Alberta saw a similar increasing trend, with fentanyl or fentanyl analogue positivity rates increasing from 4.1% in 2012 to 36.4% in 2015, spiking in 2018 to 65.9% and then increasing further, up to 80.9% in 2022. 

Ontario’s fentanyl or fentanyl analogue positivity rate increased more slowly, from 2.6% in 2012 to 20.1% in 2016; it reached 38.6% in 2017 and 68.6% in 2022. The fentanyl or fentanyl analogue positivity trends in Manitoba (rising from 2.6% in 2012 to 70.8% in 2022) and Saskatchewan (rising from 0% in 2012 to 65.3% in 2022) were very similar to those of Ontario. 

Quebec has seen different trends in its unregulated opioid supply, with overall lower rates of fentanyl or fentanyl analogue positivity. Over the 10-year period, the rates of fentanyl or fentanyl analogue positivity increased from 1.5% in 2012 to 19.1% in 2022. 

Atlantic Canada had the smallest increase in fentanyl or analogue positivity over the 10-year period. The rate increased from 1.3% in 2012 to 15.8% in 2022.

The data for 2022 showed a clear increase in the presence of fentanyl or fentanyl analogues from east to west across Canada, from the Atlantic region to British Columbia. 

Positivity for fentanyl, carfentanil and other fentanyl analogues 

The study also looked at the individual proportions of each of fentanyl, carfentanil or other fentanyl analogues in the opioid samples.

Throughout Canada, the rate of fentanyl-specific positivity in all opioid samples was 2.9% in 2012, rising to 66.6% in 2022. Carfentanil was first detected in opioid samples in 2016, accounting for 0.3% of samples that year. Its presence increased to 10.0% of opioid samples in 2019 before decreasing to 4.9% in 2022. There were notable regional differences in the proportion of opioid samples containing carfentanil. For instance, the observed increase in carfentanil positivity in 2019 was driven in part by a spike in Ontario that year. As well, it is notable that rates of carfentanil positivity in Alberta were comparatively high. In 2022, a quarter (24.4%) of Alberta samples including fentanyl or a fentanyl analogue contained carfentanil. 

Across all years, other fentanyl analogues were present in less than 10% of opioid samples. 

What does this study tell us?

This study demonstrates that there was a large increase in highly potent synthetic opioids such as fentanyl and fentanyl analogues in Canada’s unregulated opioid supply between 2012 and 2022. It also shows that there were substantial regional differences. Over the study period, the proportion of opioid samples containing these synthetic drugs increased first in British Columbia and then in Alberta, followed by Saskatchewan, Manitoba and Ontario. In the final year of the study (2022), the percentage of opioid samples that tested positive for fentanyl or fentanyl analogues increased from east to west, with the rates highest in British Columbia and lowest in Atlantic Canada. These findings underscore the importance of high-performance drug testing as a surveillance tool to better understand the unregulated drug supply. It also shows how national-level data can hide important regional differences. 

Other research has shown a clear connection between increasing overdose deaths and the rise in fentanyl in the unregulated drug supply in parts of Canada. In British Columbia, for example, the rates of drug toxicity death rose from 11.1 per 100,000 people in 2015 to 20.5 per 100,000 in 2016; during this time the percentage of opioid samples testing positive for fentanyl in the province rose considerably, from 21.3% to 61.2%. 

Implications for service providers and people who use drugs

These findings have several important implications for frontline service providers and people who use illegal opioids in Canada. First, the increasing proportion of fentanyl and fentanyl analogues in the unregulated drug supply in Canada, and in many provinces, has been associated with increased drug-related harms, and interventions are required to help reduce these harms. Second, as service providers are developing and implementing treatment strategies, especially in regions west of Quebec, they need to acknowledge the increasing toxicity of the drug supply and respond accordingly. Third, ongoing public health monitoring of the unregulated drug supply through drug checking and public health alerts is essential for keeping people who use drugs aware of the safety of the drug supply. Service providers in all regions should be aware of changing trends in their local unregulated drug supply. Finally, service providers in the Atlantic region and Quebec should be prepared for the possibility of substantial increases in overdose deaths if fentanyl and fentanyl analogues become more prevalent. 

Limitations

This study has some limitations to consider. The first is that all of the study samples were voluntarily given to the DAS by law enforcement agencies. The samples may not represent all drug seizures and represent only a tiny fraction of the wider unregulated drug supply in Canada. A second limitation is the narrow scope of the study, focusing on opioid samples adulterated with fentanyl, carfentanil and other fentanyl analogues. The study did not examine other psychoactive adulterants, such as benzodiazepines or tranquilizers, and their growing presence in the unregulated opioid supply. A third limitation is that this analysis did not consider the concentration of fentanyl, carfentanil and other fentanyl analogues in the submitted samples.

Reference

Kleinman RA. Fentanyl, carfentanil and other fentanyl analogues in Canada’s illicit opioid supply: A cross-sectional study. Drug and Alcohol Dependence Reports. 2024 May 23:100240.