There are many products used routinely for arthritis in horses.  As far as injectable products, Adequan and Legend are two of the most used injections for treatment of arthritis; both of these products are approved for this use and have been shown to be effective.  It seems horse owners are always looking for cheaper medications that will do the same job as Adequan and Legend. 

In fact, many of these medications are called generics, which they are not.  A generic medication is approved by the FDA for the same purpose as the original compound and must have the same ingredients.  For example, one of the newest medications being used for arthritis in horses is a compound called Polyglycan.  Polyglycan is sometimes called a generic form of Adequan and Legend combined, which is totally incorrect.  Polyglycan has not been approved for injectable use in horses and it does not contain the same chemical as Adequan.  Also, there are no studies showing it to be effective or safe for injection in horses.  The company that manufactures Adequan performed a study on 16 horses to compare Adequan and Polyglycan in which they gave eight horses Adequan injections and eight horses received Polyglycan.  All of these horses were injected with a chemical to induce inflammation in the knee joint.  Results indicated that 88% of the horses on Adequan had less lameness while only 50% of the horses on Polyglycan had less lameness, and 48% of the Adequan horses had reduced joint swelling while none of the Polyglycan horses had reduced swelling.  Although Polyglycan and similar products may be less expensive, most are not as effective and could be dangerous when used in an unapproved manner.