Best Buddies
Adequan® is a brand of a substance called Polysulfated glycosaminoglycan (this is one of those chemical names that is used to justify the expense of veterinary school tuition, or PSGAG, for short. It’s gained popularity as a joint protector, that is, as drug that supposedly protects cartilage, and treats joint inflammation. PSGAG has been most commonly used in cases where cartilage damage is thought to be present, with the goal of preventing, slowing, or perhaps even reversing cartilage damage. It’s also been commonly used in normal horses, under the rationale that it may help keep normal horses from doing damage to their joints when they are competing. Like Legend®, whether it can actually do all of that is another question.
PSGAG is made up mostly of chondroitin sulfate (CS), which is sometimes fed orally to horses (in any number of oral supplements), and like CS, the product is made, and then modified, from the lung and tracheal tissue of cows. There are two forms of Adequan®: one is for injection into the joint, and the other is for injection into the muscle. It’s not at all clear how well – or even whether – the products are effective, especially when injected into the muscle (the most common route of administration).
Early test tube studies on the effects of PSGAG were somewhat contradictory. Some studies conducted in test tubes on cartilage cells showed positive effects on cartilage, while others showed no effects, or even showed effects that could be construed as harmful. The thing about test tube studies is that the results can’t necessarily be carried over to a living animal – putting drugs into test tubes is a lot different than putting drugs into a horse, because the horse’s body does things to the drug that don’t occur in the test
tube.
However, results from studies on living horses are similarly confusing. So, for example, whereas a study conducted in a surgical model of osteoarthritis concluded that Adequan®, given in the joint, reduced joint inflammation and subsequent damage to cartilage caused by chemical injury, the substance absolutely did *not* help heal damage caused by the surgical procedure. And there’s no study that has shown that PSGAG helps heal cartilage damage that is already present. That means that if your horse has an arthritic joint, don’t expect that by giving it Adequan® you are going to reverse any of the
damage.
Adequan® given in the muscle seems to be very popular among horse
owners. Owners – or their trainers – typically give it to their horses in hopes that it will prevent joint damage. It’s easy to give, which, I think, is one reason for its popularity; plus, it’s a lot cheaper than Legend®. However, experimental results with the product don’t give much support for the apparent enthusiasm. It does appear to be very safe, but, then again, a saline injection would be safe, although pointless.
Given in the joint, Adequan® seems to have a more reliable anti-inflammatory effect, but not obviously anything else. When it first came out, the company recommended giving weekly injections for five weeks, but, unfortunately, some joints weren’t happy with that, and problems with acute inflammation occurred (joint “flare”) that sort of doused people’s enthusiasm for that route of administration. Plus, compared to other things that get injected into horse joints, such as corticosteroids and hyaluronan, there’s a slightly greater risk of infection; understandably, people might not be inclined to use a product if there’s a significant risk of harm.
The risk of problems from injections of PSGAG into the joint can be greatly reduced by combining it with an antibiotic. Of course, injecting any substance into a joint is something that should be done by your veterinarian,
but still, you kind of have to wonder if it’s worth the fuss, particularly since other substances, such as corticosteroids, are demonstrably as effective, more consistently effective in research studies, and a lot cheaper.
What do I think? Well, more than anything else, when it comes to Adequan® I think that you’re probably paying for your own peace of mind, and your good intentions, rather than any real therapeutic effect. Although it can be injected into joints with some reasonable expectation of an anti-inflammatory effect (but not much else), giving it in the muscle is probably not something that’s going to do your horse much good.
