Marijuana, from the Cannabis sativa plant, contains tetrahydrocannabinol (THC) that greatly affects receptors in the brain as well as various neurotransmitters. Animals can exhibit behavioral signs after about 30 minutes of ingestion and these signs can last up to three days. Dogs show a variety of clinical signs such as disorientation, tremors, hyperactivity and staggering gait. There can also be gastrointestinal signs that include hypersalivation and vomiting. The curious clinical sign that we have observed is sudden urinary incontinence. The urine will literally fall out of these dogs as they try to walk or lay in their kennel. A severe overdose of THC can result in low blood pressure, seizure, coma and even death. Treatment for THC poisoning usually involves supportive care with IV fluids, gastric intubation with activated charcoal, and tranquilizers if the patient is agitated. Life threatening clinical signs are less common but can occur. The deaths from THC intoxication that have been reported are from ingestion of marijuana butter. The concentration of THC is very high in the MJ butter and very serious intoxications can result from small ingestions of this butter (or baked goods made from this butter). Critically ill animals can have respiratory depression, low blood pressure, slow heart rates, and require intensive care as well as an antidote called intravenous lipid emulsion.
Thankfully, we have not seen severe cases in our practice as of yet. Hopefully with rapid recognition of clinical signs by the veterinarian (and clients that are forthcoming with the potential of marijuana exposure), we will manage these cases with supportive care.