This is not one of my usual posts on dog training or behavior. With marijuana being legal in many states, including here in Oregon, I had my first, and with any luck only, experience with THC toxicity in dogs.

What is THC?

Without getting too science-y, cannabinoids are the active marijuana-derived substances that have pharmaceutical activity. THC, the common name for delta 9-tetrahydrocannabinol, is a psychoactive chemical and the chief recreational cannabinoid of marijuana. This is what causes the feeling of being “high.”

How does THC affect dogs?

Although THC can product pleasant effects for humans, it is toxic for cats and dogs. Thankfully, most cases are not fatal, although smaller animals are at greater risk. A typical toxicity case involves a dog that has inadvertently eaten marijuana. In dogs, clinical signs typically begin 30 to 90 minutes after the marijuana has been ingested. Depending on the amount, the effects of marijuana ingestion can last for several days because THC is stored in fat deposits.

Common signs of THC toxicity include lethargy, dilated pupils or glassy eyes, dazed expression, difficulty walking/balancing (especially rear end), and vomiting. Other symptoms can include either a low or high heart rate, agitation, trouble regulating body temperature, and incontinence/leaking urine, tremors, seizures, and potentially coma.

See the vet!

If you notice any of these signs, take your dog to the vet immediately. Although there is not antidote per se, the vet can provide supportive help, such as fluids to counteract dehydration, anti-nausea medication to stave of vomiting, etc. Also, some of these signs are similar to symptoms caused by other poisons that are lethal. Early diagnosis can make all the difference in successfully treating your dog.

River’s THC toxicity experience

We took our usual hike Sunday morning. We don’t typically play with toys on the hike, but she grabbed a ball when getting out of the car. Who were we to argue? At one point midway through the hike, my husband tossed the ball into a creek: she loves water. When attempting to scramble out of the creek, she slipped, hitting her head on the rocks. She seemed fine, and we finished the hike without further incident.

When we returned home, she curled up on the sofa and slept. Although she changed positions a few times, she stayed on the sofa for 5 hours. River is a fairly high-drive dog so this was very unusual. We typically do some training a couple times a day. When I asked her if she wanted to do some “work,” she barely lifted her head.

I should have been worried sooner, but we had competed in barn hunt the previous day. It was unusually warm, and the trial was outside. We drove three hours each way in one day for that trial. I thought the day had just caught up with her.

Finally, I decided she needed to get up so I prompted the dogs to go outside to go potty. Zoey jumped right up, but River required some coaxing. Standing, she revealed a wet spot on the sofa. As she was walking to the back door, I noticed she wasn’t very steady on her feet. Her back end kept wobbling. She needed to be lifted down the two stairs to get outside.

Emergency vet visit

That was pretty much all I needed. We put her into the car and headed to the vet. In our minds, there were two possibilities: a concussion from hitting her head on the rocks or blue-green algae in the creek. Despite the fact that River puts everything in her mouth, I hadn’t considered that she might have eaten something else.

But the vet knew. After observing River herself and listening to our story of what had happened throughout the day, she asked if River could have gotten into marijuana. My husband and I do not use, but we do live in Oregon where it is readily available. It was certainly possible. We even knew a dog who ingested marijuana on two different occasions at two different parks.

A quick urine test confirmed the vet’s suspicion: THC toxicity. Although still worried, I was also relieved. We knew what was wrong, we knew her symptoms were relatively mild, and we knew she would be fine with time.

River was somewhat dehydrated from leaking urine and not drinking so the vet administered IV fluids. She was also given an anti-nausea medication to prevent vomiting and aspirating into her lungs. Other treatments did not seem necessary in River’s case, but other dogs could require additional care.

Seeking advice

River was back home in a couple of hours. She didn’t eat that night, and I didn’t sleep all that much. In the morning, though, she practically pounced on my husband at breakfast time. Over the next couple of hours, my spaniel returned to her spunky self!

I am thankful that her symptoms of THC toxicity were mild and short-lived. But this experience will certainly make me more cautious in the future. We are assembling a first aid kit to bring with us on hikes. For those of you who hike or camp frequently with your dogs, what do you keep in your kit for emergencies? Comment below or contact me here.