The use of cannabinoids, particularly cannabidiol (CBD) in the UK has grown in popularity in recent years. Studies suggest recent medical interest in alternative therapies and modalities has led many pet owners to seek hemp related products rich in cannabinoids.
Pet owners may not realise that the Veterinary Medicines Directorate (VMD) considers that veterinary products containing CBD are veterinary medicines, and should be regulated as such. However, there is currently no licensed CBD medicine product in the UK licensed for use in companion animals. This means that those who are wanting to try CBD in their pets often reach for over-the-counter products – which is bad for animal health and welfare for a number of reasons.
As CBD is classed as a veterinary medicine it should only be used when prescribed by a Veterinary Surgeon. Why, when online anecdotes seem so positive, aren’t veterinary professionals prescribing more CBD products? The reason is multifactorial. The evidence is still in its infancy – indeed we see many contradictory studies in animals for a range of conditions, and therefore many veterinary professionals trying to work within evidence-based medicine do not yet think that evidence is robust enough to warrant a prescription.
Secondly, veterinary surgeons have to prescribe following a cascade system. This means they have to follow guidelines that stipulate that they first prescribe a veterinary medicine that is licenced for the animal’s species and condition – CBD does not meet these criteria, and therefore there are many veterinary medications that are to be used before vets could try CBD.
Unfortunately, despite regulations to the contrary, over the counter CBD-containing products are being used by owners who are not aware of the legal constraints that govern the use of CBD in animals. For many owners, this usage is driven by the mistaken belief that cannabidiols are a natural option to try in their pets.
Owners appear to see CBD as inherently ‘safe’, with respondents in one study attributing their positive attitude towards the safety and efficacy of CBD to the belief that it was a ‘natural’ product, and therefore safe to give to their animals. However, of course, natural does not necessarily mean safe, as Prof Edzard Ernst, alternative medicine expert and fellow writer for The Skeptic, explains:
Things that are natural must be safe—this fallacy is deeply ingrained in our minds; it almost seems that, as human beings, we are hard-wired to believe this myth.
There are a number of factors why this is concerning. Firstly, over-the-counter products have been shown in the past to have unreliable contents – meaning that animal owners may be using bogus and harmful products without even realising it.
One study showed that laboratory tests from the Centre for Medicinal Cannabis found that 62% of the UK high street products studied did not contain the CBD content promised on the label, and, even more concerningly, 37% contained high levels of THC. This was further confirmed by a study that found 45% of the selected products had measurable levels of THC (mean content 0.04%) or CBN (mean content 0.01%), and are thus technically illegal within the UK. A further study found only 31% of products accurately reported the amount and concentration of CBD that they contained.
Secondly, in a number of studies there has been evidence that suggests changes in hepatic function associated with use of CBD containing product usage. The reason for this is not yet known, as there have been no long-term studies, however it has been suggested that it could be due to a toxicological response or adaptative response, as liver function returned to normal once the treatment was ceased.
Indeed, in humans the Food Standards Agency (FSA) and the Committee on Toxicology detail a number of potential toxicological effects of CBD products, that still need to be more thoroughly investigated in companion animals. The Committee on Toxicology stated:
Based on the available in vitro and in vivo data, CBD appears to have the following adverse effects: hepatotoxicity, immunotoxicity, reproductive toxicity, and interactions with drug metabolizing enzymes (P450), suggesting a risk to consumers. In addition, the effects on drug metabolizing enzymes following CBD exposure indicate the potential for drug interactions between CBD and pharmaceutical drugs.
Online anecdotal evidence for CBD is rife, so it is understandable that a worried owner will see a glimmer of hope in a treatment option that they consider both safe and, according to stories, effective.
However, owners are often not aware of the care-giver placebo effect which could account for some of the positive outcomes in anecdotes – with caregiver placebo effect being as high as 39.7%. Owners often fail to objectively assess their own pet’s condition.
Owners commonly gain information online – which could prove a downfall. For example, a study found veterinary clients ranked the internet as the third most likely source of information about pet health.
This tendency to use social media, the internet and friends or family leaves huge educational gaps in the veterinary professions ability to reach owners to provide evidence-based guidance and could certainly lead owners to accessing misinformation surrounding the use of CBD in animals.
Overall, the evidence for CBD efficacy in our pets is still in its infancy – meaning that CBD should not be used before seeking veterinary attention. Owners must arm themselves against the naturalistic fallacy – just because something appears ‘natural’, it does not mean it’s safe or effective.
