by Marcia King
With horse owners frequently clamoring for products to help manage their horses’ acute or chronic joint conditions, equine veterinarians are often called upon to make joint therapy recommendations.
Although some non-prescription items don’t get the job done due to label inaccuracy, there are reputable formulas and products that veterinarians like – drugs and ingredients backed by scientific studies, clinical research, and respectable clinical observations.
Take a look at what some experts say about what makes these products work and suitable applications for product use.
POLYSULFATED GLYCOSAMINOGLYCAN.
Brand name: ADEQUAN
Purpose: An FDA approved treatment to alleviate or reduce traumatic or chronic synovitis and related lameness, Adequan is administered intra-articularly (IA) or intra-muscularly (IM).
Studies: “In vitro evidence shows that polysulfated glycosaminoglycan reduces prostaglandin production by synovial cells — the cells responsible for most of the synovial inflammatory reaction,” says Kenneth E. Sullins, DVM, MS, Dipl ACVS, Professor of Surgery at the Marion duPont Scott Equine Medical Center, VA-MD Regional College of Veterinary Medicine.
Use: “Intra-synovial treatment is quite effective but less so than with corticosteroids (which have negative side effects),” Dr. Sullins states.
“IA is preferred for a single target joint, but should be used with caution because it can facilitate infection. Co-medication with antibiotic is recommended (not on the label).” IM is favored by those who wish to avoid infection risk, for systemic delivery, or for multiple joint problems.
“I believe Adequan’s best value is for treating generalized joint/cartilage inflammation where cartilage is still basically intact,” Dr. Sullins has found. “If the cartilage has already floated away, there is no reason to believe Adequan is more beneficial than anything else.”
GLUCOSAMINE AND/OR CHONDROITIN SULFATE.
Many brands, including COSEQUIN, CORTA-FLX, MYRISTOL and PLATINUM PERFORMANCE
Purpose: Oral nutraceuticals that promote and improve joint health. Formulas may contain additional ingredients, including fatty acids, cetyl myristoleate, green mussel (a chondroitin source), MSM, etc.
Studies: “Glucosamine/chondroitin sulfate may have anti-inflammatory properties to help with chronic joint problems,” says Nathaniel A. White, II, DVM, MS, Dipl ACVS, Director of the Marion duPont Scott Equine Medical Center, VA-MD Regional College of Veterinary Medicine.
“In vitro, glucosamine/chondroitin sulfate inhibits the release of pro-inflammatory compounds from the cartilage. In small animal and human test cases, it appears these compounds are absorbed from the intestine, potentially in large enough concentrations that they can have this antiinflammatory effect.”
In a small blinded project using force-plate measurements, Dr. White found that horses with chronic joint inflammation went sound when given Cosequin whereas horses on placebo had lameness. “There is also evidence glucosamine/chondroitin sulfate helps reduce navicular pain.”
Studies elsewhere showed that (1) horses with tarsal degenerative joint disease showed a significant reduction in gait asymmetry after receiving Corta-Flx orally for two weeks compared with a placebo treatment and (2) the effects of a glucosamine-chondroitin sulfate compound in horses with degenerative joint disease showed that lameness grade, flexion test grade and stride length improved rapidly during the first 2 weeks of administration, and then more slowly during the following 2 weeks.
Use: “Though these compounds are not extremely potent like a corticosteroid or something like Adequan, they are, to a degree, antiinflammatory and can help chronic, low level joint inflammation like arthritis. They don’t appear to give much benefit for acute joint trauma.”
As a prevention, Dr. White says he knows of no evidence to support that, but theoretically it might work.
For chronic cases, Dr. White is uncertain that horses need life-long supplementation. “It is possible that over time, the benefits have been realized, the pain isn’t there anymore, the problem is resolved in the joint and the horse doesn’t need it. I recommend owners stop the treatment and see how the horse does; the horse can always go back on it but it may be they don’t need it anymore.”
HYALURONATE ACID, SODIUM HYALURONATE, HYALURONATE SODIUM.
Injectable prescription brands include LEGEND, HYLARTIN V, HYVISC and HYALOVET
Purpose: Administered via IV or IA for acute inflammatory conditions, typically acute synovitis, acute capsulitus associated with osteoarthritis, and some injuries. Molecular weight varies among the products. Legend, Hylartin V, Hyvisc, and Hyalovet are FDA approved. (Non-prescription oral HA is also sold as a single-ingredient nutraceutical or in combination with other oral ingredients, including some glucosamine/ chondroitin sulfate compounds.)
Studies: Researchers at Colorado State University found that Legend reduces inflammation, helps repair damage to the joint capsule (synovial membrane), and indirectly protects cartilage by reducing levels of inflammatory molecules within the joint, reports Sherri Rigby, DVM, PhD, Dipl ACT and area manager, Veterinary Services, for Bayer Health Care.
“In efficacy studies of a clinical field trial, overall clinical improvement of 46 horses that were lame in the carpal or fetlock joints was judged as excellent or good in 90% of horses treated with Legend intravenously and 96% of horses treated with Legend intra-articularly,” she says.
In two CSU studies investigating Legend for prophylactic use, researchers administered Legend to racing Thoroughbreds (weekly for 3 consecutive weeks) and racing Quarter Horses in training (treated every other week for 9 months).
“Horses receiving Legend ran more races before they had to have IA joint injections, they raced with a higher speed index, and they earned more money,” Dr. Rigby says. Although the data was not statistically significant for FDA labeling purposes, it suggests prophylactic benefit.
Use: “Hyaluronate acid works better for acute conditions,” states Bruce Hebbert, a DVM, who concentrates on lameness problems at the Weatherford Equine Medical Center, Weatherford, Texas.
“If horses are really sore, it’s best to medicate the joint directly. However, we also use HA systemically after surgery, to treat arthritis, preventively in young horses and for mildly sore horses. For older horses with really bad, chronic joint problems, success is minimal.”
Other researchers and clinicians agree that use of intra-articular hyaluronic acid is indicated in instances where horses may be very lame or following surgery on a joint.
Says Dr. Sullins, “I prefer higher molecular weight products such as Hylartin V for intra-articular use. I use it at the end of surgery if I believe the ‘holes’ in the joint capsule won’t allow it to just leak out. Otherwise I begin to use it at suture removal.”
Intravenous use of HA is favored when multiple joints need to be medicated simultaneously, when joints need to be treated frequently and there is a desire not to inject a needle into the joint, or for convenience, especially when using hyaluronic acid for prophylactic purposes.
THE BOTTOM LINE
There are a lot of joint formulas out there. By sticking to the ones with good studies, science, or clinical observations behind them, and selecting products appropriate for the condition you’re treating, you could help maximize the joint health of your horse.
