Marijuana Toxicity in Dogs


Due to the recent legalization of marijuana in Canada as well as its use in foods, pills, oils and tinctures, both recreational and medical marijuana are more accessible than ever before. It’s also stronger because new hybrids and cultivation techniques have resulted in plants with significantly more THC (Delta-9 Tetrahydrocannabinol, the psychoactive compound) than in decades past. 

It therefore poses an even greater threat to one’s beloved dog since THC and other cannabinoids affect the central nervous system, causing disruption of normal movement and behavior. The most common ways for dogs to be exposed to marijuana is by inhaling its smoke or by ingesting the dried marijuana itself. Because of the cumulative effects of inhaling this smoke, dog owners who use marijuana, whether medical or recreational, should never smoke anywhere near their pets, particularly ones with asthma or any other lung diseases. 

One unforeseen consequence of legalizing marijuana may be an increased number of discarded butts or “roaches” along sidewalks and roads and throughout public spaces. People walking their dogs are advised to be on the alert for such toxic litter to ensure their pets don’t sniff out or ingest any of it.

In some cases, dogs may nibble on the leaves and/or buds of homegrown marijuana plants. Unthinking owners may also feed their dogs cookies, brownies or candies infused with marijuana, posing a double threat to their health because anything containing chocolate or the artificial sweetener, xylitol, can lead to a double dose of toxicity.

As with all products, plants and medications dangerous for pet consumption, dog owners using marijuana in any form should store it somewhere out of reach of curious noses and even more curious paws – in a tall shelf, cabinet or drawer with a child-proof lock. The use of a thick glass container with a twist-off lid provides additional security because even if your dog does discover it, the lid’s impossible to pry open.

The most common side effects of marijuana intoxication are dilated pupils, lack of coordination (falling over or walking “drunkenly”), sedation or lethargy, vomiting, urinary incontinence, and slow heart and respiratory rates. However, about 25 percent of those who have ingested THC become stimulated instead, with agitation, excessive vocalization and high heart rates being possible side effects. After ingestion, dogs can become affected in minutes to hours, and signs can last for hours.

If you suspect your dog has ingested marijuana and is unable to walk or cannot be roused, contact your vet immediately and get him prompt medical assistance. 

Treatment for marijuana intoxication can include confinement in a kennel to prevent injury, intravenous fluids to keep his blood pressure normal and medications to lower his heart rate. Dogs most severely affected may also benefit from intravenous lipid emulsions to help decrease the amount of cannabinoids circulating through their system.

The takeaway from this -- keep a watchful eye on your dog if there’s marijuana around.

Article by Nomi Berger. Nomi is the bestselling author of seven novels, one work of non-fiction, two volumes of poetry, and hundreds of articles. She lives in Toronto with her adopted Maltese, Mini, and has been writing as a volunteer for animal rescue groups in Canada and the U.S.A. since 2013.