Jan Mladonicky, DVM
Brownies on the counter? Yum! But our pets have no idea that there may be special ingredients lurking inside these tempting treats that can make them sick and are very likely to consume far more than the recommended “serving size.”
Pet toxicities are becoming increasingly more common since Colorado legalized marijuana for medicinal purposes in 2000. A published study involving two large animal hospitals from 2005-2010 demonstrated a fourfold increase in marijuana toxicities, while the number of people registered for a marijuana license increased nearly 150 times in the same time period. Now, the risk for accidental exposure and toxicity may increase further with its legalization for recreational use in January of this year: residents 21 years of age and older may purchase one ounce (~28,350 mg) at a time and can grow six cannabis plants in their homes.
Cannabis is a flowering plant used in three forms, marijuana, hashish, and hashish oil. Marijuana is made from dried leaves and flowers. Hashish and oil is made from the plant’s resin. Hemp, also originating from the cannabis plant, refers to the stalk and seed and is used for textiles, foods, paper, and body care products. All parts of the plant contain Tetrahydrocannabinal, or THC.
THC interacts with chemical signals in the brain causing (for recreational or medicinal purposes) euphoria, relief from pain and nausea, and relaxation. Marijuana is the least potent, having the lowest concentration of THC, while hashish oil is the most potent, having the highest concentration of THC. Marijuana and hashish can be smoked in hand rolled cigarettes, consumed in baked goods and candies, such as brownies, cookies, and chocolate, also known as “edibles”, or used on the skin or mouth with tinctures.
The lethal dose in animals has been determined to be about 6,600 mg per pound of body weight. Hand rolled cigarettes contain slightly less than 500 mg of THC, while “edibles” or tincture sprays can contain anywhere from 100-375 mg of THC per package or bottle. Fortunately, fatal overdoses are uncommon. However, pets can show signs of serious toxicity at much lower doses.
Just like in humans, our pets can experience unpleasant side effects when they ingest or inhale too much THC. Clinical signs include: lethargy, depression, reddened eyes, dilated pupils, abnormal eye movements, stumbling/lack of coordination, aggression, pacing, salivation, vomiting, diarrhea, muscle tremors, disorientation, fast or slow heart rate, abnormal heart rhythm, too cold or too warm body temperature, vocalization, and/or seizures. While humans share most of these symptoms, animals may also experience urinary incontinence.
These effects will last much longer in animals than humans due to differing metabolisms, weights, and volume of THC consumed. In humans, side effects can occur 10-30 minutes post ingestion, sooner if inhaled, and can last about 2 hours. In animals, effects can take 30-60 minutes, sooner if inhaled, and effects can last for days.
If these clinical signs are observed or there is any suspicion your pet has ingested marijuana, your pet may need medical care and should be evaluated by a veterinarian right away.
Being honest and upfront at the veterinary hospital will allow your veterinary care team to more quickly begin the appropriate treatment. If the ingestion occurred within the hour, vomiting may be induced. Additionally, activated charcoal may be administered to help prevent already ingested THC from reaching the bloodstream. There is an additional concern for pancreatitis or chocolate toxicity that can occur after eating “edibles” containing high amounts of fat, carbohydrates, and chocolate. If your veterinarian is not aware of the ingestion, diagnostic tests may be recommended, such as blood analysis and x-rays to help rule out organ dysfunction or a foreign body obstruction in the abdomen. The urine test used in humans to determine THC concentration is not approved for use in dogs.
There is no antidote. Treatment is supportive. Your pet will be given medications to help him/her become more comfortable, as well as fluids to combat dehydration and to help stabilize body temperature. Your pet will be released from the hospital when clinical signs disappear and she can eat and drink without vomiting. The hospital stay may be 12-24 hours or longer depending on the amount of marijuana ingested.
When bringing marijuana products into your home, please keep the THC laced baked goods and/or flower buds away from pets. If ingestion occurs, it is extremely important to bring your pet to a veterinary hospital right away for evaluation and treatment.