Nitazenes in apparent opioid toxicity deaths in Canada:

About nitazenes

Nitazenes are powerful synthetic opioids developed in the middle of the 20th century that were never approved for human consumption. Some types of nitazenes can be significantly more toxic than fentanyl and are often unexpectedly mixed with other substances, which can enhance their effects and increase the risk of poisoning. Nitazene-related poisonings can be more difficult to reverse and may require multiple doses of naloxone. They were first identified in Canada’s unregulated drug supply in 2019^{Footnote 1}.

Nitazenes involved in some opioid-related deaths

The proportion of apparent opioid toxicity deaths involving nitazenes has remained relatively stable in Canada since 2020, with less than 1% involving this subclass of opioids.

This represents a total of 15 deaths in 2020, rising to a peak of 55 deaths in 2021, before declining back to 15 deaths in 2024*.

In contrast, during the same period, more than 80% of apparent opioid toxicity deaths involved fentanyl or its analogues.

Figure 1. Percentage of apparent opioid toxicity death involving nitazenes and fentanyl or its analogues in Canada, 2020 to 2024

Table 1. Percentage of apparent opioid toxicity deaths involving nitazenes and fentanyl or its analogues in Canada, 2020 to 2024

Figure 1: Text description

Emergence of nitazenes in Canada’s unregulated drug supply

Since 2020, of all opioid identifications, the percentage of nitazene identifications ranged between 1% and 5%.

Although this subclass of opioids remains concerning due to its high toxicity, identifications remain significantly lower compared to fentanyl or its analogues, which have been found in more than 60% of all opioid identifications since 2020^{Footnote 2}.

Figure 2. Percentage of identifications including nitazenes and fentanyl or its analogues in Canada, 2020 to 2024, among all opioid identifications from Health Canada’s Drug Analysis Service

Table 2. Percentage of identifications including nitazenes and fentanyl or its analogues in Canada, 2020 to 2024, among opioid-containing samples analyzed by Health Canada’s Drug Analysis Service

Figure 2: Text description

Limitations

Deaths included in this analysis are limited to records in CCMED where nitazenes were mentioned in the cause of death statement, which relies on the medical certificate of death. No additional details on toxicology results are available. Nitazenes may not be included in routine toxicological analyses in all provinces and territories, depending on the year. CCMED data were available for 11 provinces and territories.

* Only deaths for which the death investigation was completed were included in this analysis.

Among data on drug seizures, multiple samples may originate from the same seizure, potentially leading to overcounting.

Data sources

• Mortality data were obtained from the Canadian Coroner and Medical Examiner Database (CCMED). CCMED includes all deaths that are investigated by coroners and medical examiners in Canada. For additional information visit the Canadian Coroner and Medical Examiner Database (CCMED).
• Drug Analysis Service and Cannabis Laboratory. Ottawa: Health Canada; July 2025. Findings presented here may differ from other data from the Health Canada Drug Analysis Service as these data are presented and analyzed in a different manner. For additional information about the work of the Health Canada Drug Analysis Service visit the Drug Analysis Service and Cannabis Laboratory.

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