Canada’s drug supply crisis is escalating with the emergence of nitazenes, a new and highly dangerous synthetic opioid often referred to as “fentanyl’s deadly cousin.” This substance is intensifying the risks in an already hazardous drug market, posing a severe threat to public health and leaving experts scrambling to address its devastating effects. Nitazenes were originally developed for research purposes in the mid-20th century but were never approved for medical use. Their potency, which surpasses that of both morphine and fentanyl, has made them a particularly dangerous addition to the illicit drug trade. Variants such as isotonitazene and metonitazene are frequently mixed with other substances, increasing the likelihood of accidental overdoses. Although the presence of nitazenes in Canada is relatively recent, their influence is growing rapidly. Health authorities across the country have reported an increase in overdose deaths linked to nitazenes. A significant concern is that individuals consuming drugs laced with nitazenes are often unaware of their presence. Nitazenes are commonly sold as or combined with fentanyl, heroin, or counterfeit pills, making their detection and management challenging. The unpredictability of street drugs containing nitazenes has heightened public health concerns. These substances can cause severe respiratory depression, often requiring more naloxone—an opioid overdose reversal drug—than standard doses can provide. This complicates emergency responses and places an additional burden on healthcare systems. The combination of nitazenes and fentanyl is particularly deadly. Fentanyl, already a primary driver of Canada’s opioid crisis, is now more dangerous when laced with nitazenes. This lethal mix increases the potency and unpredictability of street drugs, significantly raising the risk of fatal overdoses. The combination amplifies the challenges faced by public health officials and harm reduction programs, further straining already overstretched resources. The emergence of nitazenes in Canada is closely tied to global drug trafficking trends. These substances are synthesized in clandestine laboratories and trafficked internationally. Their extreme potency allows traffickers to transport smaller quantities, reducing detection risks while maximizing profits. A lack of regulation and monitoring has facilitated their rapid entry into illicit drug markets, complicating efforts to combat their spread. The rise of nitazenes underscores the complex and evolving nature of Canada’s opioid crisis. Public health officials are working to identify and track nitazenes, while adapting harm reduction strategies to address this new threat. However, several challenges have emerged. Standard naloxone kits may not be as effective against nitazene overdoses, often requiring higher or repeated doses. This places additional pressure on emergency responders and community organizations. The surge in overdose deaths linked to nitazenes and fentanyl has further strained healthcare systems, highlighting the urgent need for robust public health interventions. To address the crisis, a comprehensive approach is required. Enhancing drug monitoring capabilities to detect nitazenes in real time is critical. Increasing access to supervised consumption sites, where medical professionals can oversee drug use, could save lives and provide safer environments for individuals who use drugs. Public awareness campaigns are essential for informing communities about the dangers of nitazenes and educating them on how to respond to overdoses. Drug policy reforms that address the root causes of the toxic drug supply, along with efforts to reduce stigma around drug use, are also key to mitigating the crisis. On a global level, stronger international collaborations are needed to disrupt the production and trafficking of synthetic opioids like nitazenes. Canada’s opioid crisis is entering a new and dangerous phase with the rise of nitazenes. The substance’s potency, combined with its frequent presence alongside fentanyl, has created a critical public health challenge. Swift and decisive action is needed to mitigate its impact. By improving harm reduction measures, strengthening drug monitoring systems, and raising public awareness, Canada can begin to address the devastating effects of nitazenes and work toward saving lives. 24 November 2024