by Iris Winston
Nothing brings on a smile faster than watching the fun dogs have as they race around enjoying the canine company and the freedom an off-leash area offers. We had all been on a relaxing walk with our dogs when the pleasurable time quickly turned into a nightmare.
My daughter’s young German Shepherd/Blue Heeler cross, Earl Grey, suddenly turned from being joyful, bouncy and energetic into a lethargic lump. He collapsed on the grass, apparently unable to stand for more than a moment, even when we tried helping him to his feet. My daughter, a veterinary surgeon, conducted a fast examination, worried that he could be suffering from a potentially life-threatening condition such as gastric torsion (twisted stomach). But there was no sign of hardening in the abdomen area, no indication of a limb injury, no obvious sign of pain, just extreme lethargy and an odd look in his eyes.
With some difficulty, we managed to get him back to the car. (Earl weighs 72 pounds and my daughter carried him most of the way.) They sped off to the only veterinary clinic open in the city on this holiday weekend evening. After a complete blood screening and other tests, Earl was discovered to be suffering from THC poisoning.
THC (Tetrahydrocannabinol) is the principal and most active ingredient in cannabis. Dogs have a much larger number of cannabinoid receptors in their brains than do humans. They are, therefore, more sensitive to the effects of the drug. THC is highly toxic to dogs, who can react in anywhere from five minutes to 12 hours after exposure. In Earl’s case, it took just five minutes for him to show symptoms of what turned out to be marijuana toxicosis. He had been playing happily until he paused to chew something he found on the ground under a child’s swing set in the park. He came when called, but clearly not before swallowing the morsel of cannabis.
Since marijuana was made legal in Canada in October 2018 (cannabis edibles and extracts were legalized a year later) the number of dog poisonings has risen massively. It is particularly dangerous as an edible (such as a brownie or candy bar) because THC, the most harmful ingredient, is highly concentrated in the butter used in preparing these products. The secondhand smoke from marijuana is also harmful to dogs and other pets. Cats and horses are likely to suffer severe negative reactions, too, but dogs come in contact with tossed butts and discarded remnants of edible products more frequently since the drug became so accessible. (Note also that Earl found the poison near a swing set in a children’s play area.)
The most common symptoms of the toxic effects of ingesting marijuana that dogs display are stumbling, crossing their feet and generally being off balance. Dogs also become very lethargic, look dull and may have dilated pupils. Other possible symptoms include vomiting, being anxious or hyperactive and being particularly sensitive to sound and touch. Low body temperature, slow heartbeat and low blood pressure, uncontrollable urination, tremors and seizures are also among the possible symptoms, depending on the amount of cannabis ingested and the size of the dog.
Inhalation of marijuana smoke alone is rarely fatal for dogs, although it may cause a number of these symptoms. Ingestion of THC is more serious and any symptoms may last longer, usually from 24 to 36 hours. If the edible marijuana consumed contains another element toxic to dogs—chocolate or raisins, for example—additional treatment, such as inducing vomiting (if the poisoning is discovered quickly) keeping the animal warm to help stabilize his body temperature or overnight hospitalization might be required.
Fortunately for Earl, he had recovered most of his energy and enjoyment of life within 24 hours, but it took another day for him to be fully back to his mischievous self. And since his experience, I have heard of several other dogs in the area suffering from the impact of marijuana users being careless in discarding any remnants.
Almonte, Ontario, writer Iris Winston is a former executive director of the Canadian Federation of Humane Societies. She has been an animal lover all her life. Her pets have always been important members of her family.