Tuesday, July 21, 2009

Joint supplements - a vet's perspective

Question 1:"what are the best and least expensive joint supplements to use on my horse for healthy joints?"

Question 2: "what are the benefits of Adequan vs Legend?"

Answer by Susan Garlinghouse, DVM, MS:

Answer 1: Here’s my opinion about joint supplements, both oral and injectable.

There’s no data to support that providing any sort of supplement prior to actual clinical signs of degenerative joint disease actually delays its eventual onset. However---if we consider what we ask these horses to do, even the best conditioned, most intelligently managed horse is going to have *some* degree of inflammation in its joints after a ride, and even though that inflammation may be insufficient to appear on an x-ray or in a lameness exam, it makes sense to protect those joints as much as possible. As such, I give my horses joint supplements when they’re working hard; and the 17-year-old campaigner I’m currently riding is getting practically marinated in the stuff, even though he doesn’t have a whisper of lameness, just because he’s working hard and is seventeen years old.

Of the oral forms of supplements, the best data available is from NutraMax Labs, that developed and markets the original oral supplement, Cosequin. They do show a measurable benefit provided by regular dosing, BUT---even the most expensive, name brand stuff out there only has a bioavailability of about 3-4%---which means you have to feed boatloads of it to get a smidgen of it into the circulation where it can eventually be taken up by inflamed joint tissue. Pretty expensive stuff for most of it to end up in a poop pile (though I’m happy to report the flies on my property feeding on that poop have never looked so spry). The bioavailability goes down when you get into the generic versions---even though the ingredient label may still say “chondroitin sulfate”, the label doesn’t tell you the Daltons (size, more or less) of the molecule in question. The bigger (read “cheaper”) the molecule, the less likely it is to be absorbed in the GI tract and thus get used effectively. There’s a good bit of data that supports the notion that most of the generic joint supplements available at Costco don’t do a darn thing, just because the molecule is too big to be absorbed. And remember, the very BEST source out there is only 3-4% available when fed orally.

That being said, I hugely prefer going the injectable route, because then I’m bypassing the GI tract entirely and most of the injected dose is getting to inflamed tissue where it belongs. Yes, I know the injectables are more expensive per dose, but I’d rather pay more for a vial of liquid gold that’s almost entirely bioavailable, then paying a lot less for an oral supplement that’s mostly ending up in the manure dumpster. Even I can do that math. I’ve heard differing things about the oral hyaluronates, but still prefer going the direct injectable route with that as well, for basically the same reasons.

Because I own an animal hospital and mostly work on companion animals for a living, I use the injectables in a whole lot of different species and it helps a bunch, especially in creaky, arthritic old dogs. Sometimes it’s hard to see a tangible difference in horses that are still pretty much moving okay, but I know a dog is feeling better when he starts asking to go for walks again, jumping into the car without help, whatever. I always tell my owners not to expect a miraculous improvement overnight, because we’re not just masking symptoms with a painkiller, we’re approaching the source of the disease process directly, and that takes some time. I usually dispense enough for the initial loading period of six weeks or so and sometimes then I’ll ask the owners if they saw an improvement and would they like a refill. Sometimes they tell me they didn’t see much benefit, so nope, they’ll skip the refill. I can pretty much set my watch that a month later, they’ll be calling for that refill, because they didn’t realize how much better old Duffy was until they STOPPED giving him the Adequan. I’d guess I probably have about a hundred patients on it in my practice at any given time.

I couldn’t tell you the efficacy of the generic injectables. I know they’re out there, but I use the brand name Adequan and/or Legend in my practice, just because I’m positive those are effective, and I need to use that not only for my own animals, but also for my clients.

So, I know you’re looking for something inexpensive to feed, but I’m going to go out on a limb and also assume you want the most bang for your buck. My advice would be to skip all the oral supplements entirely, with the possible exception of some source of omega-3 fatty acids, which have a different mode of action but are still pretty good for assorted inflammatory conditions, including those affecting the joints. The most cost-effective source of the O-3s is maybe a cup or two of freshly ground whole flax seed---grind it up yourself in an electric coffee grinder, stick it in baggies into the freezer and give your horse a baggie once a day.

Take whatever your annual budget is that you were planning on spending on oral joint supplements and figure out how much Adequan, or Legend, or both, that you can afford. Do that. Resis the urge to feed something other than the aforementioned flax seed. You’ll get more benefit from an Adequan or Legend injection once a month, or twice a year, or whatever suits your budget, than you will by feeding the oral supplements on a daily basis---especially if the oral supplement is one of the cheap ones that oh-by-the-way, has such low bioavailability that 99% of it is going into the dumpster.

Hope this helps. BTW, all the above comments also apply to arthritic dogs, kitties, bunnies and darn near every other species out there. I won’t comment publicly on its applicability to humans, because I’m not licensed for that species and the DEA would be sending me nastygrams as soon as they finished tracking down whoever it was that sold propofol to Michael Jackson.

Susan Garlinghouse, DVM

Answer 2:
That’s a really good question, and I’m going to go out on a limb here and assume you’re interested more in a practical answer than debating the p-values and historical influence of the senate subcommittees on its use, so forgive me if I gloss over some of the finer biochemical details. Both Adequan and Legend tend to achieve the same end goal of by slightly different pathways. Both have the end effect of increasing the concentration of hyaluronic acid in joint capsules and tendon sheath (and a few other assorted locations). Hyaluronic acid is a nifty little ‘backbone’ molecule that binds water within the joint fluid---the best analogy I can think of is one of those coat hangers with all the clips on it for hanging pants and skirts and things. The more coat hangers you have, the more things you can grab onto. So, the more hyaluronic acid, the more water molecules you can grab. That’s handy, because water is about the only substance on earth that doesn’t compress under pressure and so is a really great shock absorber within the joints. That helps prevent rubbing and friction within the joint during high-concussion which is likely to result in inflammation and, over time, arthritis.

So Adequan acts by stimulating the cells that line the cartilage (that’s the layer inside the joint capsule that covers the ends of the bones) to naturally produce more hyaluronic acid. Legend is actual hyaluronate itself, which after injection, is preferentially taken up by inflamed tissues throughout the body, including within joints. Dunno how the body ‘knows’ but that applies to lots of different processes in the body we still haven’t figured out but are happy to take advantage of, anyway. Hyaluronate is also commonly one of the substances injected directly into a joint, usually along with a small amount of a long-acting steroid, but that will only directly affect one joint; whereas systemic administration will affect pretty much all the joints within the body, though to a lesser overall extent. If you’ve ever heard of a horse getting his hocks injected (or knee, or fetlock or coffin joint), that’s what they’re talking about. Not something you do lightly, though, because directly injecting a joint is definitely a veterinary procedure that has to be done exactly right.

If you absolutely had to choose between Adequan or Legend, then the general concensus in the online vet community (we have our own discussion groups where we chat about this kind of thing and no, they’re not open to non-vets) is that Adequan is preferred if you have soft tissue involvement (like tendons and ligaments), and Legend is a bit preferred for straight arthritic conditions. Adequan, of course, also benefits arthritic conditions as well, but seems a bit better for general wear-and-tear. If you want the absolute best of both worlds, then do both, and that’s what I do for my horses that are working hard or have some issues they’re dealing with.

If I had to choose between one or the other for preventative maintenance, then I would probably go with Adequan, because I think it benefits tendon and ligaments as well as strictly joints a little better, and I want to cover as many bases as possible. For an older horse with DJD, then I think you’ll get more benefit with Legend. As I said, though, the gold standard would be both but hey, we can’t all wake up with Oprah Winfrey’s budget every morning.

Someone else asked me if they could only afford a few injections a year if there would be any ‘spiking’ effects and no, there’s no downside to less frequent dosing except that you’re just not getting as much benefit as you would with frequent administration. If I had to time it around a riding season, I would probably use up my budget starting a month or so before the first ride, when presumably, you’re starting to ramp up workouts. If you can give the horse some additional during the season, better. If you can give them some more right at the end of the season when they’re about ready for a rest and probably have some active inflammation to one extent or another, that would be great.

The other question someone asked me was whether this was something an owner could do, versus having to call out the vet. Adequan is an intramuscular injection, so most owners can do that. Some drugs (like procaine penicillin) you have to be careful to keep out of veins and such, but Adequan isn’t a problem if you happen to hit a vein. Some of the racetrack people prefer Adequan IV, though I go IM myself. Legend might be bioavailable if you injected it IM, but is best IV---so if an owner were comfortable doing an IV injection themselves, fine. It’s legal for an owner to administer meds to their own horse by any route, but starts getting into gray areas doing it to anyone else’s horse, aside from potential liability problems if you do it wrong. So if your vet is willing to supply you with either Adequan and/or Legend, and/or you’re otherwise able to obtain it somewhere (I don’t know if you can buy it online without a prescription, you probably can), and you’re comfortable injecting your own horse, go for it.

Hope this helps.

Susan Garlinghouse, DVM, MS

No comments: