I first began writing about potential medical uses for cannabis products in pets ten years ago. AT the time, there was weak evidence for a few uses in humans, and almost no research evidence in dogs or cats. Since then, I have covered the topic frequently, and new evidence has appeared regularly. This evidence has been mixed, with some studies suggesting benefits and others not. Generally, the safety data has suggested minimal risk, though a recent recommendation to lower the maximum daily dose of CBD in humans reflects the fact that there is much we still don’t know about the potential consequences of long-term use of cannabis-based compounds.
It is currently vogue to use CBD for a wide-range of problems in dogs and cats, and there is little to no evidence to support most of these uses. The most common use, and that with the best evidence, is for pain. However, even in humans there is controversy about how effective CBD and other cannabis-based compounds are for pain. A recent systematic review found that,
“Studies in this field have unclear or high risk of bias, and outcomes had GRADE rating of low- or very low-quality evidence. We have little confidence in the estimates of effect. The evidence neither supports nor refutes claims of efficacy and safety for cannabinoids, cannabis, or CBM in the management of pain.”
A similar systematic review was recently published for the use of CBD in treatment of arthritis in dogs.
Patikorn C, Nerapusee O, Soontornvipart K, Lawonyawut K, Musikpodok K, Waleethanaphan K, Anantachoti P. Efficacy and safety of cannabidiol for the treatment of canine osteoarthritis: a systematic review and meta-analysis of animal intervention studies. Front Vet Sci. 2023 Sep 15;10:1248417.
As a refresher, a systematic review is the highest level of research evidence available for most questions. It involves the explicit and formal finding and analysis of controlled research studies on a given topic. Such reviews are not perfect nor free from bias, and they are less useful the less roust the primary research evidence is, but they give the best overview of an issue based on the highest quality evidence currently available.
The conclusion of this review is typical of many in veterinary medicine:
“Five articles were included, which investigated the effects of CBD in 117 dogs with OA. All studies were rated as having a high risk of bias.
CBD is considered safe for treating canine OA. CBD may reduce pain scores, but the evidence is very uncertain to conclude its clinical efficacy. High-quality clinical trials are needed to further evaluate the roles of CBD in canine OA.”
There have been relatively few studies involving few patients and all with significant methodological risk of bias. From this kind of evidence base, the best we can safely conclude is that CBD might have some benefits for dogs in pain and probably doesn’t have any acute risks.
That is sufficient to consider adding it in as a treatment for dogs with arthritis not sufficiently controlled by other treatments, but NOT to use it as a first-line treatment or a substitute for treatments with better evidence for efficacy (such as non-steroidal anti-inflammatory drugs).