Marijuana, other recreational drugs debut on pet toxins top 10 list

For the first time, recreational drugs have made the American Society for the Prevention of Cruelty to Animals (ASPCA) Animal Poison Control Center's (APCC) annual list of top toxins for pets. These drugs include marijuana-based substances, hallucinogenic mushrooms, and cocaine, which took the tenth spot on the list.

Over-the-counter medications, most often pain medications such as ibuprofen and acetaminophen; food, especially protein bars, xylitol gums, and grapes or raisins; and human prescription medications held the top three spots, respectively.

In 2022, the APCC team assisted 278,364 animals from the U.S., resulting in a nearly 5% increase in call volume when compared with 2021. The team received almost 11% more calls related to potential marijuana ingestion than in the previous year, and they have seen a nearly 300% increase in calls over the past five years, according to a recent APCC press release.

The most common cases the center saw involved pets ingesting marijuana-laced baked goods. In these cases, there may be additional toxic ingredients involved—such as chocolate, raisins, or xylitol—which result in a poorer prognosis. The most common clinical signs in dogs are ataxia or incoordination and lethargy or depression. Other common clinical signs are vomiting, urinary incontinence, increased sensitivity to motion or sound, head bobbing, dilated pupils, increased salivation, and a slower than normal heart rate.

Dr. Justine Lee, a board-certified veterinary emergency critical care specialist and toxicologist, explained that with the legalization of marijuana in several states and provinces, there has been an associated increased prevalence of accidental exposure to dogs, and children and less commonly cats.

"As a result, we need to be aware of this toxicant. Less frequently in the veterinary ER do I see cocaine or hallucinogenic mushrooms," said Dr. Lee

According to a study published in April 2022 in PLoS One, researchers conducted a survey of veterinarians in Canada and the U.S. and found 226 of 251 toxicosis cases were among dogs. They also found that 116 of the cases were suspected to be from ingestion of edibles when the pet was unattended. Cannabis toxicosis was mostly diagnosed using supportive clinical signs, and the most common treatment was outpatient monitoring.

"The legalization of cannabis use in Canada and the US is likely an important factor associated with the increased cannabis toxicosis cases in pets; however, the legal status may also increase reporting," the authors wrote. "The medicinal use of cannabis by pet-owners for pets may also contribute to a portion of the reported toxicoses. Most pets that experienced cannabis toxicosis recovered completely, suggesting that most cannabis toxicoses do not result in long-term ill effects."

Dr. Lee said that pet owners are often unwilling to admit to illicit drug toxicosis.

"Judicious, nonjudgmental history taking, along with rapid recognition of clinical signs, is imperative to rapidly allow for decontamination—if appropriate—and treatment," Dr. Lee said.

More information about cannabis use and pets is available on the AVMA website, including the document "Cannabis in veterinary medicine" (PDF).

A version of this story appears in the August 2023 print issue of JAVMA.