The afflicted animals often became very disoriented or lethargic and had abnormally slow heart rates, but most made a complete recovery, the researchers reported on April 20 in the journal PLoS ONE.
Veterinarians have been taking note of an increase in pet poisoning linked to cannabis, she adds, and the research team from Canada validate the trend with the new data.
But until this point, data about the magnitude of this problem have been sparse, says Jibran Khokhar, a neuroscientist at the Ontario Veterinary College at the University of Guelph and coauthor of the findings.
When he and his collaborators surveyed 191 veterinarians in Canada and 60 in the US, they observed that the amount of cannabis poisoning cases increased in both countries after fall 2018.
One explanation for this shift is that the increased availability of cannabis products meant for people has led to more pets encountering the substance since legalization in 2018 in Canada .
The veterinarians noted a wide variety of symptoms that ranged from very common .
Generally, the animals recovered after being monitored or receiving treatments such as intravenous fluids or anti-vomiting medication.
Although cannabis poisoning was most common in dogs, the veterinarians also treated cats, iguanas, ferrets, horses, and cockatoos.
The data can contain flaws due to human error: Owners may have not remembered—or been willing to share—the full details of their pet’s exposure to cannabis.
In the future, it would also be helpful for researchers to investigate what dosages are needed to cause life-threatening symptoms in animals, Haraschak says.
Khokhar hopes the new report will raise awareness among pet owners about cannabis poisoning.
“We don’t call the police or report anybody, especially with it being legal now; that part is not our concern,” Haraschak says.
She frequently covers nature, climate, and the COVID-19 pandemic, but has also reported on many other aspects of science, including space, paleontology, and health.