Montreal public health officials issue overdose alert after 8 recent carfentanil deaths

Montreal public health officials are issuing a new warning of fatal overdoses involving carfentanil, after eight new deaths were reported since its last overdose alert in April.

That number may also be underestimated, the public health agency stated, due to lab confirmation delays.

The number of non-fatal overdoses linked to fentanyl use also remains very high, requiring emergency interventions including many ambulance transports, according to the Montreal regional public health sector of Santé Québec.

The health department says paramedics have administered naloxone more than 925 times since the start of the year, which is 25 times more than in all of 2025.

“For the past three to four months now, we’ve been seeing a significant increase in the total number of overdoses in Montreal. And then in terms of emergency responses—for example, ambulance calls due to overdoses—that trend is continuing.

This is concerning because it’s a sustained trend," said Dr. David Kaiser, the Montreal regional public health department’s deputy medical director.

Naloxone blocks the body’s receptors that absorb opioids such as fentanyl, heroin, morphine, and oxycodone, and its use by paramedics is considered an indicator of overdose trends.

Carfentanil, an opioid so toxic it can be lethal at very low doses, is being regularly detected in mixtures sold as fentanyl, typically in the form of rocks of various colours.

The mixtures also contain other similar drugs, such as medetomidine, a veterinary sedative that has been circulating in Montreal’s fentanyl supply for months, as well as benzodiazepines.

Public health is urging people who use drugs to be cautious regardless of how they consume, to avoid using alone, and to reduce their usual doses, since even a very small amount of these drugs can cause an overdose.

Anyone spending time with a person who uses drugs should have naloxone on hand and know how to use it. Public health notes that the antidote is not dangerous even if it turns out not to be needed.

Signs of overdose include difficulty breathing or snore-like gurgling, minimal or no reaction to noise and pain, bluish lips and fingernails, and pinpoint pupils. Anyone witnessing an overdose should call 911 immediately. The Good Samaritan Drug Overdose Act protects witnesses who call from prosecution for simple possession.

Sante Quebec also recommends users visit supervised consumption sites and drug-checking services, while cautioning that carfentanil may not always be detected in testing. Free naloxone is available at Quebec pharmacies.

Kaiser is also asking members of the public to intervene if they see someone who appears to be struggling to breathe, unresponsive, or who appears to be in an “altered state.”

They can give naloxone if they have it, and should call 911 as soon as possible, he said.

Kaiser noted that the growing homelessness crisis is part of the issue.

“We know that there is an intersection between the housing crisis, the homelessness crisis, and the crisis involving harmful drugs,” he said.

“For example, people with mental health issues or other health needs. We know that if they have housing and are connected to services, they will be better able to manage their drug use—or even reduce it."

With files from The Canadian Press