In 2013, I wrote about a particular medical marijuana product marketed for veterinary use, Canna-pet, as an illustration of the uncertainties and issues surrounding the potential medical use of cannabis-derived products. At that time, my conclusion was that 1) there is enough pre-clinical evidence to suggest cannabinoids of various types have physiologic effects that could prove beneficial, 2) there is limited evidence for some clinical use in humans, 3) but overall the evidence in humans is weak, 4) and in veterinary species it is non-existent.
Sadly, the state of the evidence hasn’t changed in the intervening couple of years, but the marketing of such products to pet owners and veterinarians has continued to grow. The lack of meaningful regulation of dietary supplements allows the sale of unproven remedies so long as the benefits are only implied and not directly stated. This loophole has created a wonderful opportunity for companies to profit from products that might or might work and might or might not be safe. This does not strike me as serving the best interests of patients. The money and energy put into marketing these products could be better used to fund research to identify the true risks and benefits.
The only veterinary “research” that has emerged recently is the kind that I have discussed many times before, research that is intended to sell an idea or product rather than to find out the truth about it. This is the kind of research most preferred by companies selling such products and by alternative medicine advocates such as the AHVMA, and both are involved in this particular study.
Consumers’ perceptions of hemp products for animals. JAHVMA. Spring, 2016, vol. 2
The full details of the study are not available except to subscribers, but the results are summarized on the AHVMA web site, and this summary has been widely distributed by Canna-Pet. It consistent of an online survey “provided by Canna-Pet to their customers.” Obviously, this represents clear selection bias, since those responding to the survey are going to be those buying a hemp product for use in their pets because they expect or hope it will help. Anyone who doesn’t have a pre-existing bias in favor of using such a product, or who has used it and had negative experiences, is not going to be a customer and so is not going to participate in this survey.
Of the 632 respondents, about half felt it had helped their pet with pain, sleep, anxiety, and in cats inflammation. No data are provided on the conditions for which owners felt it wasn’t helpful or any other relevant information about the animals or their conditions, other treatments, and so on.
About 15-20% of owners reported undesirable effects, such as sedation or excessive appetite.
There is no way to evaluate this survey without more information, other than to say that it appears to contain no controls whatsoever for bias. As such, it is likely to be as unreliable as most online testimonials. And it is actually a bit surprising that even with a survey that doesn’t control for bias, the best the company could say about the results was that only about half of the users of the product felt it was beneficial. Not a powerful endorsement given the exclusion of likely sources of negative feedback.
In any case, such a survey at most represents attitudes towards cannabis products and says nothing about whether or not they actually work. However, the media and advocates for veterinary use of cannabis are certainly spinning it as at least implying such products are effective or worth a try.
As I mentioned in my previous post, the good news about the diminishing stigma associated with marijuana is the possibility of real research into chemical compounds that will likely prove to have medical benefits. The bad news is that there is some evidence legalization has led to an increase in marijuana poisoning for dogs, and it has provided more opportunities for companies to get into the business of selling the potential benefits of cannabis-based products before doing the necessary work of proving these benefits exist and that they are worth the risks.
One example of this is a new company vying with Canna-Pet for this potentially lucrative market, Canna Companion. This company is a little more circumspect in their claims for the medical effects of their product, but they still aggressively promote it as a “holistic” therapy, playing on the mythology that things labeled “holistic” or “natural” can be assumed to be safe based on pre-clinical evidence or anecdote alone and don’t require the rigorous clinical testing conventional therapies are expected to undergo.
The company web site, like that of Canna-Pet, doesn’t discuss any clinical studies in companion animals since there aren’t any. They simply point to the basic science research that shows the potential for benefits from cannabis-based products. Such research often fails to live up to its promise when specific products are tested in real-world patients, but this never seems to be a concern for companies marketing untested products. The company certainly has some legitimate scientists working for them, and their Chief Clinical Epidemiologist is a well-qualified public health researcher at the NC State Veterinary College. Such an individual should be well-suited to organizing rigorous scientific evaluation of cannabis-based products. I was, therefore, quite disappointed by the very unscientific his experience and credentials are used to promote the product:
Professor Peter Cowen of North Carolina State Unversity’s College of Veterinary Medicine and now the Company’s Chief Clinical Epidemiologist and an Advosiry Board member commented: “Based on my own experience with my dog, Londun, there is something of extreme value here. I am impressed not only from a therapeutic perspective, but also from a psychological perspective.” Professor Cowen is orchestrating a clincial study at NSCU for the coming year and the Company is looking forward to presenting those findings to the veterinary community and the public at large.
An anecdote from an epidemiologist is worth no more than an anecdote from anyone else, and the company certainly sounds like the results of the study they are planning are a foregone conclusion. The risk of bias here is, obviously, quite high, and I wonder how eager Canna Companion will be to promote the results if they turn out not to support the product, unlikely as that is. Only time will tell.
That might also be the most appropriate conclusion to the question of whether or not cannabis-based products are useful for veterinary patients. At the moment, there is no reliable evidence, so only time will tell. Hopefully, the pursuit of profits before science won’t lead to too many animals being exposed to useless of even harmful substances before we have the data we need to know what cannabis-based products might be useful for which problems.