Overview of Marijuana Toxicity
Living in California where marijuana use is now legal, marijuana toxicity in dogs is becoming increasingly more common. The toxicity can even occur out in public places, such as parks and hiking trails. The toxic principle of marijuana is tetrahydrocannabinol or THC. The amount of THC found within the plant products depends on the environmental factors in which the plant is grown, or in some cases is listed on the packaging of edible type products. The THC is rapidly absorbed from the gastrointestinal tract and is lipid or fat soluble so distributes to other fat stores within the body. Once it is absorbed it is metabolized or broken down by the liver, but it can also cross the blood brain barrier and take direct action on receptors within the brain, which often attributes to the clinical signs observed by marijuana toxicity.
Clinical Signs of Marijuana Toxicity
The most common signs reported with marijuana toxicity include depression, ataxia (or a wobbly gait), incoordination, vomiting, tremors, increased pupil size (mydriasis), hypothermia, disorientation, hypersalivation, hyperexcitability or inappropriate vocalization. Depending on the severity of the toxicity this can progress to a stuporus or comatose type state or even seizures. They can also develop a severely depressed heart rate or a very fast heart rate. The clinical signs of marijuana toxicity often occur approximately within 30-60 minutes after ingestion and can last for 24-72 hours depending on the amount ingested.
The urine of dogs that potentially be tested for the presence of cannabinoids. The bench top test that is often used is a human drug screen test, which is not very sensitive for the presence of these substances in the dog urine. Essentially if tested and the dog urine comes back as positive, the dog is suffering from marijuana toxicity. However, if the test comes back negative and the dog is still exhibiting signs of marijuana toxicity, it could still have ingested some marijuana (false negative test). The urine or even stomach contents can be sent to specific laboratories to test for the presence of cannabinoids, but by the time the results come back the dog will likely have recovered.
Treatment for marijuana toxicity often involves supportive care. Depending on how affected the dog is from the toxicity, hospitalization may be recommended, or supportive care can also be attempted at home. If the ingestion was recent, vomiting may be induced, but if the dog is not mentally aware enough this may not be pursued to avoid aspiration pneumonia. If the ingestion was also recent activated charcoal may be recommended, but this will also depend on the mental awareness of the dog at the time. Supportive care often consists of fluids under the skin to assist with hydration and an anti-nausea medication if they are vomiting. If the dog requires hospitalization, they may require intravenous fluids, a special drip of triglycerides or other therapies. Most dogs recover completely in 24-72 hours and often do not require any additional therapies once recovered.