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Canadian Researchers Warn of Edibles’ Risks

By Alexander Beadle

Published: Jan 08, 2020   
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Following the recent legalization of cannabis edibles in Canada, two of the country's scientists have penned a commentary in the Canadian Medical Association Journal warning physicians and the general public of the novel risks presented by edible cannabis products.

"Although edibles are commonly viewed as a safer and more desirable alternative to smoked or vaped cannabis, physicians and the public should be aware of several risks related to the use of cannabis edibles,” wrote Drs Jasleen Grewal and Lawrence Loh, respectively of the Department of Family and Community Medicine and the Dalla Lana School of Public Health at the University of Toronto, Ontario.

Edibles may carry an increased risk of overconsumption 

Chief among the scientists’ concerns is that consumers who are ‘cannabis-naive’ may end up overdosing on cannabis from overconsumption. 

As the scientists explained, it can take longer for cannabis edibles to produce noticeable effects of intoxication than smoked cannabis. The intoxicating effects produced by cannabis edibles are also thought to last for a longer period of time overall. 

“The onset of psychoactive effects from cannabis edibles can be delayed by up to four hours after consumption, and the effects can last for more than eight hours overall,” wrote the researchers. “[This] lengthens the duration of impaired judgment and coordination experienced in comparison to inhaled cannabis.”

The concern is that individuals who are unaware of this difference might decide to ingest further doses of edible cannabis products soon after an initial dose, mistakenly believing that the first dose had no effect. Serious overconsumption of cannabis can lead to feelings of extreme anxiety, headaches, and an elevated heart rate. In extreme cases, or where there are pre-existing health issues, overconsumption can also result in seizures, psychotic episodes, or heart attack. 

The commentary authors do note that Canada’s new regulations on edible cannabis products require the disclosure of standard dosing information on purchasable edibles, and impose restrictions on the maximum THC amounts allowable per serving. Still, they advise that individuals take care even while following dosing recommendations as “individuals’ responses to different products may vary and overdosing may still occur.”

Children and older adults most at risk, say authors

In particular, the scientists warn that children and older adults may be at a higher risk of harm following the legalization of cannabis edibles. 

“Children (and pets) are at risk of accidental ingestion and overconsumption of cannabis because many edibles resemble candy or other food and drink,” wrote the researchers. Additionally, they cited information gathered following Colorado’s legalization cannabis edibles, where the state reportedly saw a 70 percent increase in calls to the state poison control center over accidental cannabis exposure in children between 2013 and 2017. 

While people aged 65 and over-report the lowest rate of cannabis use overall by age group, cannabis use in this demographic has begun to grow following legalization. More commonly now, older adults are reporting using cannabis to manage symptoms of chronic health conditions as the stigma surrounding cannabis use lessens.

Referring to the findings of a 2014 review on cannabinoid use by older populations, the authors of this new commentary caution that for “older adults, cannabis consumption – including use of edibles – has been linked to greater cognitive impairment and a heightened risk of hypotension-related falls, arrhythmia and drug interactions.”

Canadian regulations now require edibles to be stored and sold in plain, child-resistant packaging in order to curtail the risks of accidental ingestion by young children. Packing is also required to display relevant standardized symbols and health warnings, with strict limits imposed on any marketing or promotional claims printed on the packaging. 

“Physicians should routinely question patients who ask about cannabis about their use or intended use of edible cannabis products so that they can counsel these patients regarding child safety, potential for accidental overconsumption and delayed effects, and potential for interactions with other substances such as alcohol, benzodiazepines, sleeping aids, and opioids,” the authors wrote.

With continued population-level monitoring and evaluation, the authors say, regulators will be more able to control the availability of both legal and illicit products and to mitigate any negative effects on individual and community health.

Alexander Beadle

Science Writer

Alexander Beadle has been working as a freelance science writer since 2017 and has covered the cannabis industry for Analytical Cannabis since 2018. He has also written for our sister publication, Technology Networks, and the cannabis industry consultant firm Prohibition Partners, among others. Alexander holds a Master's in Materials Chemistry from the University of St. Andrews, where he won a Chemistry Purdie scholarship, and conducted research into zeolite crystal growth mechanisms and the action of single-molecule transistors.


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