Effective therapeutic cannabis doses have not been worked out in pets. It is best to start with the lowest amount possible and to gradually increase the dose every 5 days or so until the desired effect is seen. If undesired side effects such as excessive sedation, disorientation, excitement, vomiting etc. are observed, the cannabis dose is too high and administration should stopped immediately. After the side effects have worn off, the animal can be restarted at a lower dose. The upper oral dose limit for CBD products recommended by veterinarian Dr. Robert Silver is around 1 mg/kg/day orally, but one should start with a much smaller fraction of this dose such as 0.05 mg/kg/day. For THC products, Dr. Silver recommends to start with an oral dose of 0.1-0.25 mg/kg THC once or twice daily. Once the pet has received the same dose over about 1 week without undesired effects, the pet has developed a tolerance and the dose can be gradually increased.
How to calculate your pet’s starting dose?
A new pharmacokinetic and clinical study recently completed at Cornell suggests that 2 mg/kg of cannabidiol (CBD) oil twice daily can help increase comfort and activity in dogs with osteoarthritis. The abstract was submitted to the 2017 American College of Veterinary Surgeons Summit in Indianapolis and is pending peer review.
Example 1: Commercial CBD oil
Let’s say your dog weighs 55 lb = 25 kg (55÷2.2) and the hemp oil you bought lists 200 mg of CBD infused in 1 oz olive oil. Your dog’s starting dose of 0.05 mg/kg/day calculates as 1.25 mg/day (25 kg x 0.05 mg). One fluid ounce equals approximately 30 ml, so the hemp oil has a CBD content of 6.7 mg/ml (200÷30). Your dog’s starting dose of 1.25 mg equals a volume of approximately 0.2 ml of the hemp oil (1.25÷6.7). Since olive oil contains approximately 20 drops per ml, 0.2 ml equal about 4 drops (0.2×20). Your starting dose is 4 drops by mouth once daily for 5 days.
Example 2: Home-made Cannabis Oil
Let’s say you want to make an herbal oil infusion of the dried cannabis flowers and leaves you bought legally at a dispensary. A strain with a CBD content of 15% and a THC content of 20% contains 150 mg CBD and 200 mg THC, respectively, per one gram of plant material. If you infuse 5 gram of this strain in 200 ml of olive oil using the double-boiler method, your oil will contain 750 mg CBD and 1000 mg of THC, or 3.75 mg/ml CBD and 5 mg/ml THC. Assuming your cat weighs 11 lbs (5 kg), her starting dose of 0.1 mg/kg/day equals an oral dose of 0.5 mg per day. Since each ml of your oil infusion contains 5 mg THC your cat’s starting dose is 0.1 ml or approximately 2 drops by mouth once daily for 5 days.
For more information on how to make an herbal infusion see instructions below.
Example 3: Cannabis of Undetermined Potency
Start with the smallest possible amount. Depending on your pet’s weight that may be as low as 1 drop or 1 capsule once daily. Observe for undesired effects such as loopy behavior or sedation and if none is observed continue the same dose for 5 days before gradually increasing the dose to desired effect.
It is safer to use legal industrial hemp products for pets since they contain nearly no THC and have high amounts of medicinally valuable CBD and other nonpsychotropic cannabinoids, terpenes and terpenoids. There is risk of toxicity and expensive emergency visits if your pet is given too much THC or gets accidentally into marijuana products. Be aware, that many edible cannabis products for humans contain ingredients toxic to pets, such as xylitol, macademia nuts and chocolate. There have been two cases reported in the literature of dogs dying from marijuana, both of these dogs ingested cannabis products containing chocolate, which appears to have a negative cumulative toxic effect. Always keep our own edibles and your pets’ cannabis products safely stored away from pets and children.
References & Resources
Cannabis sativa L: Its Botany and Potential Value to Veterinary Medicine. VBMA Teleseminar July 2015. Robert J. Silver DVM, MS, CVA