Cannabis-Induced Poisoning In Pets Sees Uptick: Study

As marijuana gets legalized in more and more places, there has been an uptick in cases of cannabis poisoning among pets, a survey of veterinarians has found.

The cannabis legalizations across North America have coincided with an increase in cannabis-induced toxicosis in pets, noted the authors of a new study published in PLOS ONE on Wednesday. However, the exact "magnitude" of the increasing issue, as well as how these cases turned out, has been unknown.

"In fact, a study in Colorado found a strong correlation between the number of registered medical cannabis cardholders and cases of cannabis toxicosis in dogs, with a 4-fold increase in reported cases between 2005 and 2010," the researchers wrote. "Additionally, over the past 6 years, there was a 448% increase in reports of cannabis poisoning cases in companion animals in the United States (USA) and Canada."

For their work, the researchers conducted an online survey of over 200 veterinarians in the U.S. and Canada between January and April 2021. The results revealed that most of the cannabis toxicosis cases were reported in dogs, and other animals such as cats, iguanas, ferrets, horses and cockatoos were also affected. The cases in both countries saw an uptick after October 2018. This was the year when Canada legalized marijuana, noted HealthDay.

"(I)n both Canada and the US, the number of cannabis toxicosis cases increased significantly after October 2018 (which coincided with legalization in Canada, but not the US)," the researchers wrote. "Additionally, of those who reported a change (85/211), nearly all (82/85) reported an increase in the number of cases."

Among the most common clinical signs reported were urinary incontinence, disorientation and lethargy. The most common route was exposure was through oral ingestion, with edibles often suspected to have caused cannabis toxicosis.

Most of the pets ended up recovering completely from the condition, with many of them being treated with outpatient care. However, there were 16 cases wherein the pets ended up dying in association with the cannabis exposure, noted the researchers.

According to the researchers, it's possible that the increase in pet owners' medicinal cannabis use as well as the increase in reporting due to the legalizations may have contributed to the increasing trend.

"When it was illegal, it was harder to get them to admit," Dr. Elizabeth Rozanski, a critical care veterinarian at Tufts University's Foster Hospital for Small Animals, said as per HealthDay. She was not among the authors of the study. "They thought we would report it to the police — which we wouldn't."

Overall, the results of the study suggest that "most cannabis toxicoses do not result in long-term ill effects," according to the researchers. In the instances that resulted in death, other factors such as underlying conditions as well as the presence of other toxins such as chocolate, xylitol and illicit drugs "cannot be ruled out."

"Most dogs will recover but you'd rather not see them go through this," Rozanski said, as per HealthDay.

As such, cannabis' potential for lethality in pets needs further investigation. The researchers also noted the need for more sensitive tests to diagnose cannabis toxicity.

"As the burgeoning field of medicinal cannabis use in humans and animals continues to grow, fundamental research into the pharmacokinetics, pharmacodynamics, and potential lethality of cannabis in different animal species is also needed to address outstanding research gaps," the researchers wrote.