Last Friday, the Veterinary Medicines Directorate (VMD) released, rather out of the blue, a really surprising press release. The VMD is the regulator for the manufacture, sale, prescription and use of veterinary medicines in the UK, and in this press release, they have formally declared that “The VMD considers that veterinary products containing Cannabidiol [CBD, a substance derived from the cannabis plant] are veterinary medicines.” In this blog, we’re going to be looking at the consequences of this ruling!


What does it mean to be considered as a veterinary medicine?

While it may seem logical that any medicine given to animals is by definition a veterinary medicine, this isn’t actually the case. A veterinary medicine is defined as being either:

  • Medicinal by presentation – in that it gives the averagely well informed person the impression that it treats, cures or otherwise influences a disease state (i.e. the manufacturer says it does something). This is why most food supplements and tonics, for example, do not state that they treat disease – just that they may “support animals with” a condition.
  • Medicinal by function – in that it has a significant and measurable effect on the body (i.e. it actually does do something).

Any product or active ingredient that meets either of these criteria comes under the regulation of the VMD. If a product is ineffective, and does nothing at all, the VMD aren’t interested unless the manufacturer is defrauding their customers by claiming that it does. On the other hand, if it does work, then it definitely comes under their purview.


Why did they make this change?

The press release states that they consider that cannabidiol to be “medicinal by function” – in other words, they have concluded that it does in fact have a clinical effect on animal’s bodies. The reasons behind this sudden change in opinion are not immediately clear, but personally I suspect that there are three major factors:

  1. There is a great deal of interest in cannabidiol’s therapeutic properties in human medicine – even the World Health Organisation (WHO) has now issued a formal review of it. There’s actually a cannabidiol medication licensed in the USA now for use in humans for some (quite rare) types of epilepsy. If a drug has a biological effect on one mammal species (humans), it is likely to have effects (if not exactly the same) on other distantly related species (such as dogs or cats). It would be rather perverse for the VMD to claim it was ineffective in animals when the WHO is citing animal studies in their research.
  2. As a result of several high-profile cases of children with epileptic disorders whose symptoms were reportedly alleviated by cannabis-based medications, this summer the UK government announced a relaxation of the regulations around these products – this is probably part of that process.
  3. Increasing numbers of animal owners are sourcing cannabidiol as a “nutritional supplement” but are using it to treat disease, in some cases apparently without veterinary input. This is seen as a concern for animal welfare, because products manufactured as food supplements are not as well regulated as medicines which have a potent active ingredient.


What is cannabidiol, and what is it used for?

Cannabidiol – or CBD – is a natural product of the cannabis plant. There are a huge number of potentially active ingredients in the plant, but most interest has focussed on two – Tetrahydrocannabinol (THC), the psychoactive, moderately addictive and possibly pro-seizure, pro-anxiety component; and CBD, which many researchers believe has the opposite properties.

In human medicine, the best evidence is for use in certain treatment-resistant forms of epilepsy. There is however some evidence that it may be effective in some other conditions, especially as a painkiller, for reducing anxiety, for modulating the immune response, and for managing side effects of other medications, among others.

Unfortunately, the evidence for its effectiveness is still rather weak, with some studies finding very positive results and others struggling to confirm them. In animals, there is relatively little evidence of the drug’s effectiveness, although some American vets are experimenting with it for its pain relief properties, and at least one study has suggested a clinical effect. Anecdotally, some vets are reporting great results, but there is always the risk of unconscious bias in these situations, which is why we need well-designed clinical trials and studies.


OK it’s considered as a medicine – so what?

Well this is where it gets a bit controversial. It is illegal for any person to use a medicine in an animal unless the medication is licensed and authorised (there is a partial exception for medications prescribed by a vet). As a result, it is now illegal to buy any CBD products to give them to animals unless you have a veterinary prescription for it.


Surely that’s outrageous? They’ve decided that it works so they’re going to ban it!

Not quite! While they thought the drug didn’t do anything, there wasn’t a problem – because while it might not help the patient, it wouldn’t do any harm either. However, now that the evidence suggests it does work, that means it may have significant side effects if used inappropriately. By bringing it under regulation, anyone who wants to sell it must prove two things before they get a license – first, that it does actually work (and not just one single trial, but a whole series of data), and second, that it is in fact safe for use at such-and-such a dose in a particular species. This is the whole point of the veterinary medicines regulations – to make sure that we know what the risks and the benefits of using it actually are (not just the hype from the manufacturers), so that you and your vet can make an educated decision as to whether or not it is suitable for your pet.


What does this mean for my pet?

If you are already using CBD, you need to talk to your vet about getting a prescription for it. With a prescription, you can legally purchase human CBD products (there aren’t yet any licensed veterinary forms); without one, you are breaking the law.

However… if you aren’t, this change in the law has been widely circulated among the profession, and I suspect a lot of vets who were very skeptical before might be more willing to trial the product now.

In either case, if you think your pet may have a condition that might benefit from CBD, it’s time for a conversation with your vet about it. It may be that it doesn’t work in animals – we don’t know for sure yet – but if it does, it could be a very valuable addition to our armoury.