Fatal incident underlines the need for stricter oversight of diphenhydramine sales in Quebec (2023)

Hitting the Sleep Button too Hard: A Look at Diphenhydramine Overdose and its Potential Regulation

Montreal's coroner is pushing for a closer watch on antihistamine and sedative diphenhydramine, following a fatal overdose of an 18-year-old man in a town nearby in late 2023.

This chap, whose identity remains undisclosed, met his end due to acute diphenhydramine poisoning amidst a peaceful slumber in his St-Mathias-sur-Richelieu home. On the fateful morning of December 11, 2023, his grieving mother discovered an unresponsive and supine figure of her son in his bed. Toxicological analysis determined lethal amounts of diphenhydramine coursed through the victim's veins.

Known as the sleep-inducing component in popular over-the-counter antihistamines like Benadryl, this substance can prove deadly if misused.

Unbeknownst to the government's regulatory bodies, the circumstances around this sad tale awakened questions about the ongoing unchecked availability of a potentially lethal over-the-counter substance. The coroner's report highlights a consensus within scientific communities about the dangers of poisoning, yet the drug remains unrestricted in public pharmacies.

"What the fuck is this madness?" coroner Vincent Denault ponders. "How can diphenhydramine, a substance associated with numerous deaths, be accessible under the counter?"

The report, published in April but released this week, attributes the man's death to the acute toxicity of diphenhydramine, a central nervous system depressant. When ingested in excess, this substance causes fatal respiratory depression and irregular heartbeat, which can result in fatal cardiac arrhythmias.

An empty collection of diphenhydramine jars and blister packs lies among the man's belongings, raising questions about his nightly routine.

"Was he popping these suckers to catch some z's? Did he chow down on a heap of these things during the night of December 10-11, 2023?" Denault muses.

Not the first time diphenhydramine has claimed a life, Denault has weighed in on no less than four previous Quebec investigations. In 2020 there was an alarming spike in diphenhydramine-related deaths following a hazardous social media trend known as the Benadryl TikTok challenge.

Those goddamn TikTok trends, enticing the youth into dangerous practices, causing untold damage and claiming innocent lives. What a fucking disgrace to our society, Denault mutters under his breath.

Sure, kids take it for its hallucinogenic and euphoric effects, and some even make the ultimate decision to bid farewell to this world. But we should take more stringent measures to prevent another tragedy like this, Denault pleads.

His recommendation? The provincial office of professions to amend regulations involving the sale of pharmaceutical products, relegating diphenhydramine to a category requiring additional pharmacist oversight. These enhanced controls include maintaining a detailed file of each sale, conducting a pharmacological study on the file, and ensuring that the drug is parked behind the pharmacist's counter.

The heads of the province's College of Physicians and the body overseeing pharmacists in Quebec, Jean-François Desgagné, will review Denault's recommendations to determine whether the drug needs a change of scenery.

This report by The Canadian Press was first published May 10, 2025.

Background:

Diphenhydramine is a widely available antihistamine and sedative found in various over-the-counter medications. Some lots of the drug have recently been recalled due to contaminants[2]. Its misuse can lead to fatal overdoses, as was the case in this instance[1][3].
There have been calls for stricter regulations and controls on diphenhydramine and other over-the-counter medications due to concerns over misuse and poisoning[1][3].
There is ongoing conversation about improving the process for switching prescription drugs to over-the-counter status, which may indirectly impact over-the-counter drug regulations[4][5].

The coroner in Toronto is advocating for stricter regulations on diphenhydramine, an over-the-counter antihistamine and sedative linked to a fatal overdose in a nearby town in 2023.
Media outlets have been covering the investigation, focusing on the appropriateness of diphenhydramine's unchecked availability in health-and-wellness sections of stores.
The victim, whose identity has not been disclosed, died due to acute diphenhydramine poisoning, with lethal amounts detected in a toxicological analysis.
Questions have been raised about the suitability of keeping diphenhydramine accessible without pharmacist oversight, given the drug's potential for misuse and the associated deaths.
The coroner's report has highlighted concerns within scientific communities about the dangers of diphenhydramine poisoning, urging mental-health and health-and-wellness stakeholders to reconsider the drug's classification.
The proposal suggests amending the regulations involving the sale of pharmaceutical products, shifting diphenhydramine to a category requiring additional pharmacist oversight, such as maintaining a sales record, conducting a pharmacological study on the file, and keeping the drug behind the pharmacist's counter.