Article by Sam Riches, Growth Op
Cannabis extracts, including disposable vape pens, became legal in Canada in October 2019. Around the same time, an outbreak of severe lung disease linked to vaping was unfolding in the U.S.
The EVALI (an acronym referring to an e-cigarette, or vaping, product use associated lung injury) outbreak illustrated the need for tested and regulated products.
In the U.S., where cannabis remains federally illegal, there have been 68 deaths and more than 2,800 hospitalizations, across all 50 states, due to vaping-related illnesses or injury, with most cases linked to illicit cannabis vapes.
As of August 2020, 20 cases of vaping-associated lung illness had been reported to the Public Health Agency of Canada, including five cases linked to vaping Tetrahydrocannabinol (THC) only, and three linked to Nicotine, THC and other substances. It’s not clear where the vapes were purchased.
Cannabis vapes, while banned for sale in Quebec and Newfoundland and Labrador, face more stringent regulations than other legal products. Still, questions remain about the safety of the products that have been legally available for 17 months. Here’s what we know so far.
Regulated by the Cannabis Act, cannabis vapes are not permitted to contain anything other than carrier substances, flavouring agents, and substances that are necessary to maintain the quality or stability of the product. Nicotine, caffeine and ethyl alcohol are banned. As are colouring agents, sugars, sweeteners, and mineral nutrients and vitamins, including vitamin E acetate, an ingredient strongly implicated in the EVALI outbreak by The United States Centers for Disease Control and Prevention (CDC).
Vitamin E acetate has been found in patient lung fluid samples tested by CDC and in product samples tested by the U.S. Food and Drug Administration.
“The 2019 EVALI crisis was a real eye-opener because what it showed was that we can’t assume that what’s in these e-liquids is inherently safe,” Dr. Mark Ware, chief medical officer for Canopy Growth, tells The GrowthOp.
Last July, Canopy stopped selling third-party vapes in its corporately owned retail stores and franchise retail locations that included added phytol, a terpene that occurs naturally in cannabis in small amounts. That decision was informed by a study commissioned by the company and published in the journal Inhalation Toxicology. The study, which was conducted on rats, found there was no safe exposure range for phytol when used as an excipient in a vaping product.
The study compared the potential toxicity of phytol, which Canopy does not add to its vapes, and propylene glycol, which is commonly used as a thinning agent in the e-cigarette industry. Sprague Dawley rats were exposed to 5 mg/L of phytol or propylene glycol for up to six hours a day, over the course of 14 days.
After only one or two days the rats exposed to phytol expressed severe clinical signs, including bodyweight loss, damage to respiratory tissue and mortality.
“Very rapidly, it was clear that the inhaled phytol caused significant harm to the animals that were involved in the research. And in fact, we’ve terminated the study early because of that,” says Dr. Ware.
The propylene glycol arm of the study continued, however, and exposed animals did not show any adverse reactions after 14 days of high dose exposure. A review of toxicological data published by the National Academies of Sciences, Engineering, and Medicine found that oral exposure to propylene glycol is not likely to be associated with adverse health effects. However, the review noted that the data for inhalation exposure, including long-term effects, is limited.
“Because we couldn’t be sure how much phytol was in these different third-party products, we felt the sensible thing to do from our perspective was to take them off, and then let the regulator make the remaining decisions about how they wanted to regulate phytol going forward,” says Dr. Ware.
The findings were shared with Health Canada in late July before the study was peer-reviewed and published.
In a statement to The GrowthOp, a Health Canada spokesperson said licence holders that produce vapes and other inhalable products were informed of the study and asked to gather more information on products that may contain added phytol. Licence holders were also asked to identify any available safety-related data, studies, or adverse reactions related to phytol in inhalable cannabis products.
“Based on the responses received, Health Canada determined that there was a small number of products on the legal market that contained added phytol and that most had low concentration levels of less than two per cent,” the spokesperson said.
No serious adverse reactions have been reported to Health Canada from licence holders. They also haven’t received reports of adverse reactions regarding phytol-containing vaping products from health care practitioners or individuals.
“Health Canada is not aware of any direct evidence that low concentration levels of phytol in cannabis vaping products that are available in the legal market may cause injury to the health of the user when used as intended,” the spokesperson said.
Health Canada also noted the limitations of Canopy-backed study, including that the study was not designed to determine a safe dose of phytol and “some of the particularly long durations of exposure to phytol in the study (i.e., up to six hours per day) are not necessarily reflective of real-world use.”
Health Canada said it continues to monitor evidence as it emerges to determine the applicability to any cannabis vaping products currently on the Canadian market and adds that the Department will take action if it identifies a product that poses a risk to public health and safety, or is non-compliant with the Cannabis Act or its Regulations.
Under federal regulations, licence holders are not permitted to sell any cannabis products that “may cause injury to the health of the user when used as intended or in a reasonably foreseeable way.”
And while licence holders are required to retain records on the ingredients contained in their vapes, and ingredients are visible on the product label, consumers are increasingly calling for a more detailed breakdown of vaping products, including terpene concentrations.