VETS CORNER Marijuana (THC) Poisoning
By Dr. Kelly Wasylciw, Norwood Veterinary Services
The legalization for recreational use of marijuana in Canada has been seen with any other medi-
cation - the increased accessibility to the drug has led to an increase in accidental exposure in pets. Marijuana can cause severe toxicity to your pet. Tetrahydrocannabinol (THC) is considered the most active and main psychoactive agent and varies from 1% to 8%. Owners having any products with THC in their householdshould take great care to ensure their animals can’t get into it. Dogs and cats will readily eat THC products (including the plant itself ), so it’s the most common way an animal will be intoxicated by the drug, but not the only one. Animals can also become intoxicated by inhaling second-hand smoke, so keep pets away when smoking inside. Dogs and cats have more cannabinoid receptors in their brains. A small amount is all it takes to cause toxicity compared to humans. Common signs of marijuana toxicosis in dogs and cats are depression, stumbling (ataxia), low heart rate (bradycardia), lower body temperature (hypothermia), vocalization, hypersalivation, vomiting, diarrhea, urinary incontinence, dilated pupils (mydriasis) and, in severe cases, even seizures or coma. These signs can begin within 30 minutes of ingestion and can last up to 72 hours. THC is stored in fat tissue and moves easily into these areas. It gets into the liver, brain and kidneys and can be stored there before leaving the body. This is why the effects can last so long, as all of the stored THC has to be metabolized by the body and excreted before the effects fully wear off. Diagnosis is based on history of exposure, typical clinical signs and can usually be confirmed by a urine drug test, which will quickly show results in clinic. Sometimes, just like any test, it is possible to get a false negative, so veterinarians need owners to be honest about their pet’s potential to ex-
posure and consumption of THC. Ruling out THC poisoning is absolutely critical for these patients to get the care they need. If the exposure is very recent, induced vomiting (emesis) can be considered, however there are two factors that may interfere with this approach. The first is that the signs of toxicity may manifest only after the drug has been absorbed, meaning it is too late to make the animal vomit. The second is that cannabis has an anti-emetic effect, which inhibits vomiting. Symptomatic treatment and monitoring should continue until all clinical signs have resolved. This can be done at home safely or at other times it is in the pet’s best interest to be at a clinic for care. For severe marijuana toxicosis, IV lipid emulsion solution may be considered to help remove the THC. This emulsion pulls the THC out because it binds to the lipids (fats) in the IV solution. Although intoxication is seldom fatal, some medical grade products or edibles have extremely high levels of THC and can cause a lethal overdose. This is why it’s important to provide that information to your veterinarian to direct treatment options. Other compounds found within Marijuana, such as cannabidiol (CBD), have shown promise for medicinal use and are being researched further. If you believe your pet has been exposed to Marijuana, contact your veterinarian & provide all relevant information, so they can properly treat your pet. Also, most veterinarians are not concerned with your ‘extra-curriculars’ and won’t judge you. They are there to assist in helping your pet feel better. 61