Carfentanil Drug Alert: Public Health Officials Warn of Extremely Potent Synthetic Opioids in the Drug Supply
Health officials are once again warning communities about the growing presence of carfentanil and other dangerous synthetic substances in the illicit drug supply after a surge in overdoses triggered multiple emergency alerts across Ontario.
A public health advisory issued on May 12 by the Northwestern Health Unit warned that a substance being sold under the name “Dizzy” is believed to contain carfentanil, an ultra-potent synthetic opioid. Experts estimate carfentanil is approximately 100 times stronger than FYL, 4,000 times more powerful than heroin and nearly 10,000 times stronger than morphine.
The warning followed a sudden spike in overdoses in Kenora, where community partners reported 11 non-fatal overdoses connected to the substance in a single day.
Shelly McLarty, program manager for sexual health and outreach services at the Northwestern Health Unit, said carfentanil has appeared periodically throughout the region over the last several years, though it remains especially dangerous due to its potency.
“We’ve seen episodes over the past few years where carfentanil surfaced in our communities,” McLarty explained. “Most people generally avoid it unless they can’t access the substances they usually use because awareness has increased around just how powerful it is — even compared to FYL.”
Health experts warn that only a few tiny grains of carfentanil can trigger a fatal overdose.
Multiple Drug Alerts Issued Across Ontario
The Kenora alert is not an isolated incident. Earlier this month, another warning was issued through the Lifeguard app after testing conducted by NorWest Community Health Centres in Thunder Bay identified carfentanil mixed into a substance initially believed to be FYL.
That sample, described as a dark blue substance, was analyzed on May 4 and found to contain several dangerous compounds.
Just days later, another advisory warned the public about crack cocaine contaminated with FYL analogues and other unknown substances.
According to Juanita Lawson, CEO of NorWest Community Health Centres, carfentanil was identified in four out of 66 samples of suspected FYL tested by the organization’s mobile drug-checking program between June 2025 and April 2026.
Lawson noted that health workers are also seeing increased detection of veterinary sedatives and synthetic additives, including medetomidine, XYL and fluorofentanyl.
“These substances continue appearing more frequently in the drug supply,” Lawson said. “The combinations are becoming increasingly unpredictable and dangerous.”
Veterinary Sedatives Continue to Complicate Overdose Responses
Public health agencies are especially concerned about substances such as medetomidine and XYL, both veterinary tranquilizers not approved for human use.
While these drugs may be mixed with opioids to extend or alter effects, they create serious complications during overdoses because they do not respond to Naloxone the same way opioids do.
Officials emphasize that Naloxone should still always be administered during any suspected opioid overdose because FYL or other opioids are often present. However, people may require additional medical treatment, oxygen support or prolonged emergency care due to the sedative effects of non-opioid contaminants.
The Thunder Bay District Health Unit first warned residents about carfentanil circulating locally back in 2018, but officials say the current drug supply is becoming increasingly unstable as more novel synthetic substances appear.
Harm Reduction Experts Encourage Safety Precautions
Health workers are urging people who use substances to take additional precautions due to the unpredictable and toxic nature of the current drug supply.
Recommended safety measures include:
- Avoid using drugs alone whenever possible
- Carry multiple doses of Naloxone and know how to use it
- Call 911 immediately during a suspected overdose
- Use drug-checking services or test strips before consuming substances
- Utilize overdose monitoring services such as the National Overdose Response Service (NORS) or the Lifeguard Digital Health app
McLarty stressed the importance of testing substances before use, especially because many drugs now contain hidden synthetic opioids, tranquilizers or benzodiazepines.
“People should check substances beforehand to identify anything unexpected,” she said. “If something dangerous is detected, it may give them a chance to reconsider using it.”
She also emphasized that emergency medical assistance remains critical even after Naloxone is administered.
“Some individuals may need ongoing medical support for hours or even days depending on what substances were involved,” McLarty explained.
Counterfeit and Contaminated Drugs Continue Driving Overdose Risk
Public health experts say today’s illicit drug market is increasingly defined by contamination and unpredictability. Substances sold as cocaine, crack, prescription pills or heroin may actually contain mixtures of FYL analogues, carfentanil, nitazenes, benzodiazepines, XYL or veterinary sedatives without the user’s knowledge.
This growing trend significantly increases overdose risk because individuals often consume substances without knowing their true strength or contents.
Drug-checking programs across Canada and the United States continue identifying new synthetic opioids and sedatives entering the market, many of which are far stronger than traditional opioids and more difficult to respond to during emergencies.
Health officials continue encouraging communities to expand access to Naloxone, overdose education, supervised consumption services, substance testing and harm reduction support as overdose deaths remain a major public health concern.
Source: NWO News Watch