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Ask the Doctor September 2016 Issue

Dear Doctor - Cosequin and its effects on cats

Little is known about whether or not certain supplements actually benefit our cats

Cosequin and its effects on cats

Dreamstime.com

Well-designed studies are essential to help us understand what works.

Q In the July 2016 of Catnip, there was an article on the value of joint supplements, highlighting the fact that there has not been any research focusing on the value of glucosamine and chondroitin in cats. While I have not seen any research papers either, I have had positive personal experience with these supplements with multiple cats.

One of my cats, a large and healthy male, suddenly lost interest in food and was acting as if he was in pain. X-rays at my vet’s office showed arthritis of the spine. We put him on ‘Cosequin for Cats,’ a glucosamine and chondroitin supplement in measured caplets. I gave him two a day for the first 30 days. After the first dose, he started eating again.

After about a week, he was jumping up on the bed again and acting normally. I cut back to one caplet a day after the first month, then cut back to once a week after that —and finally cut back to only giving him one when he seemed to be stiff or sore. As my other cats aged and starting showing signs of joint problems, I would give them Cosequin daily for a week or two, then cut back to only as needed. When the joint issues became chronic, I would keep them on a twice-per-week dosage. It appeared to be effective with all four cats I have given it to so far.

I hope you find this information useful, and can share it with other Catnip readers.
Phoenix Von Hendy

A Dear Phoenix: Thank you for your interesting letter. I have a few observations to make about the subject of analgesic supplements and medications in general.

Firstly, we are more inclined to use a neutraceutical product because of the impression that it may be associated with fewer serious adverse effects than a drug. And when a cat’s mobility and personality improve specifically related to administration of any substance or procedure, it is quite reasonable to attribute the response to the substance or procedure itself.

Scientists have conducted scores of clinical experiments in both humans and animals investigating the pain and mobility improving effects of glucosamine and chondroitin containing supplements. Glucosamine has been shown to alter inflammation in both in vitro and in “whole patient” studies, and this may be why some patients seem to find relief from this particular neutraceutical. In fact, in humans, a European prescription glucosamine formulation has been found to be especially effective, whereas other types do not appear beneficial in studies.

This finding underscores the fact that — as Dr. Heinze indicates in the article you mention — the effectiveness of the supplement may depend highly on its precise source, the manufacturing process AND how it is stored and shipped. Check any pet store or catalog and you will find a wide array of products that purport to improve pain and mobility.

The reality is: Unless the product has been demonstrated to improve signs of disease compared with a placebo in a well-designed study, we must be cautious about concluding that the product does what it says it will do.

Also, products that undergo FDA approval must be screened before approval and then monitored continuously for potential adverse effects. It is common to find that some supplement manufacturers do not collect data and so have not reported adverse effects of their product — for example, gastrointestinal upset in some pets from glucosamine containing products. This is something that pet owners discover by chance and which resolves on discontinuation of the product, but may make its way only slowly into the medical literature.

Well-designed studies that help us understand what works and whether it causes harm are essential. We also would prefer not to spend money on non-effective strategies. Large scale clinical trials are the best way to get effective and safe products into our cats. So if you ever have the opportunity to participate with your cat in a clinical trial of a supplement, or to help fund research, you will help our aging cat population live comfortably without arthritis pain.

In the meantime, it remains trial and error and anecdote with our ouchy kitties. What matters most is that they seem to recover their agility and essential “catness.” If they do this and have no side effects, then there is little reason not to continue giving the supplement.

But back to the placebo effect in animals — and whether there is such a thing or not. The placebo effect is an important feature of scientific studies, and a study is just not well regarded unless the product or procedure is compared with placebo treatment. “A placebo effect is any medical intervention that has a favorable, non-specific, psychological or psycho-physiological therapeutic effect, but without specific activity for the condition being treated” to quote one veterinary research group. (Jaeger et al, 2005).

In pain studies in humans, the percentage of people who report improvement in pain while taking the placebo pill or treatment is on average 30 percent (Price et al, 2008). One possible reason for improvement is that humans “expect” to get better and complex mental and physiologic explanations have been proposed. But your cat has no idea that the pill you are giving might or should make him better, you say. He has no such expectation.

However, veterinarians and pet owners alike must face this fact — in study after study of pain medications, the improvement in comfort or mobility reported by the dog owner ranges from 30 percent to 57 percent and that estimated by the veterinarian assessing the patient ranges from 40 to 45 percent in the placebo group!

We actually report an improvement in pain due to placebo that is greater than what humans report for themselves. In some cases, objective evidence (pain, weight-bearing and overall condition scores) demonstrates that the patient has NOT improved with the placebo treatment. This apparent improvement on placebo is known as the “caregiver effect” — and while it is a phenomenon that is not yet well studied, there is widespread agreement among veterinary researchers that studies to prove the effectiveness of a variety of medications or treatments in animals must be conducted carefully and a successful treatment should prove better than how animals in the placebo group fare.

It is thought that the caregiver’s estimation of the degree of improvement is in fact due to our own expectations of the result of giving a medication, and so we over-interpret the result. But also, many diseases and also veterinary therapies have the potential to be impacted by the ways a pet caregivers’ behavior may change. We ourselves may strongly influence the outcome when we treat our pets because of poorly understood mechanisms related to our interactions with them. This is an area of health care that deserves active research.
Alicia M. Karas, DVM, MS, DACVAA
Anesthesiologist, pain management
Cummings School of
Veterinary Medicine
at Tufts University

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