MAR 09, 2010

This is not a "testimonial" intended for the commercial betterment of any one brand. It just so happens that the only version of polysulfated glycosaminoglycans (PSGAG) in the veterinary marketplace is Adequan. And it works.

Poly what?? OK, so it doesn’t really matter to me that you can’t pronounce this alphabet-soupy injectable drug. It’s enough for me that you know what it does so you can ask your veterinarian about it the next time your cat or dog suffers conditions for which it might prove beneficial.

The conditions? Officially, the menu is a short one, as it’s currently approved only for use in dogs and horses "for the treatment of noninfectious degenerative and/or traumatic arthritis and associated lameness of canine and equine synovial joints." So says my Plumb’s Online Veterinary Drug Handbook (courtesy of VIN).

Unofficially, however, this drug is used safely in cats for the same indication: joint pain. Increasingly, veterinarians are turning to it for felines as a result of our extremely limited arsenal of pain-relieving drugs for this species. We’re not about to wait for approval when we all know our cats receive a pittance of the research funds that dogs do. Might as well use it "off label" ... if it’s safe. And we think it is.

Though Adequan is labeled as a drug, most veterinarians don’t tend to think of it in these terms. That’s because it’s derived from cow tracheas and only slightly modified in a laboratory to make it more stable. As such, it’s more like a nutraceutical (think glucosamine and chondroitin sulfate, which this drug more closely resembles than any NSAID we may use for pain relief).

Yet while it’s considered way safer than NSAIDs (Rimadyl, Metacam, et. al.), make no mistake: it’s not a 100 percent safe product. Toxicology studies have found that when megadoses are administered, liver and kidney changes are observed. Even in moderately over-large doses, platelet numbers are reduced and blood clotting problems may result. Furthermore, a small percentage of these overdosed dogs showed pain at their injection sites (I've never noticed this in my patients so the discomfort may be related to the larger volumes administered to these test subjects).

Yes, Adequan is delivered as an injection. It goes in the muscle. For horses, it’s also approved for injection inside the joint. (I don’t know anyone using it this way in dogs, but I’m sure someone out there does.) And it’s only available by prescription through your veterinarian. Luckily, most vets I know are willing to show you how to give it — that is, if you’re brave enough to want to learn.

OK, so enough about Adequan’s gruesome origins, side-effects, and delivery options. How does this stuff work? Though the mechanism by which Adequan makes joints feel better isn’t well understood, its action is an anti-inflammatory, cartilage-protecting one. We believe it acts by inhibiting enzymes that break down the cartilage within joints and by increasing the thickness of joint fluid.

But that’s not enough to completely explain how it reduces inflammation. Given that Adequan also seems to work to reduce swelling in the bladder and help repair corneas, it’s clear there’s more going on with this drug than meets the eye (pardon the pun).

Though it’s not been approved for use in these conditions, and research to prove that this efficacy is more than anecdotal is still pending, feline veterinarians have been using it for the dreaded kitty condition known as interstitial cystitis (AKA, feline idiopathic cystitis), while horse vets in Brazil tested it out on indolent corneal ulcers and found that their patients' eye lesions healed much faster than their control subject counterparts.

I’ve never tried it out on eyes, and I’m waiting for more of a consensus on that front before mixing it into eye drops myself (though a quick search on VIN showed that vets out there are using it with some success). I do, however, use it in my feline patients to manage their arthritis and to reduce the symptoms associated with many urinary conditions. I’ve been using it for years in this way and always thought it made at least a slight difference. In fact, some cats experienced such a tremendous benefit, I’ve taken to trying it out on all of my arthritic kitties and inflamed feline urinary tracts.

For dogs and cats alike, my basic approach has been the same as of a few months ago: eight shots over four weeks (I used to use a longer course with less frequent dosing). I use it less often at a slightly lower dose for those whose kidneys and liver are in some way compromised, and I always lower (or eliminate) the NSAID or steroid dose for those who are also taking these or any other drugs that have the possibility of inhibiting platelet function or "thinning the blood."

But don’t just take my word for it. Consider that veterinarians everywhere are starting to get in on the Adequan act. With our pets living longer, we recognize the need to more carefully manage our pain relievers. Using this less side-effect fraught alternative approach to treating pain and inflammation may just be what your vet orders, too. So go ahead, ask.

Dr. Patty Khuly