Note: This article originally appeared in the May 2003 issue of EQUUS magazine. The product, Surpass, has since been approved and is available through veterinarians.
A new topical cream in the final stages of Food and Drug Administration (FDA) review promises to provide a targeted means of treating equine joint soreness without the risk of the gastrointestinal and renal side effects associated with systemic nonsteroidal anti-inflammatory drugs (NSAIDs).
The cream, under development by IDEXX Pharmaceuticals, contains the active ingredient diclofenac, an NSAID commonly used to treat arthritis pain in people. To facilitate its absorption through the skin, the diclofenac is encapsulated in a liposome formulation. "The cream can be rubbed directly onto the area of the horse where pain relief is needed," says Joseph Bertone, DVM, who participated in a study of the product's efficacy as part of the FDA approval process.
Bertone tested the cream on 122 horses with previously diagnosed lameness in one or more joints. At the beginning of the study, each horse was assigned a lameness score between 0 and 5 and pain and mobility scores from 0 to 100 percent. Blood was also collected. The horses were then randomly assigned to a placebo or a treatment group. Owners of the horses in the treatment group were given tubes of the diclofenac cream, and owners of placebo-group horses received identical tubes filled with a common hand lotion. The horses were treated daily for five days, and an independent researcher, who did not know whether the subjects were receiving the treatment or the placebos, examined each horse daily to record levels of lameness, pain and mobility. On the final day of treatment, blood was drawn again.
The results, says Bertone, were "surprisingly good." When the data were analyzed, the researchers found that 77 percent of the horses treated with diclofenac had a reduction in their lameness, while only 30 percent of the control group improved.
No adverse effects were noted from the treatment. "I think this product is going to be a great alternative to systemic drugs," says Bertone. "Rather than expose the horse's entire system to a large dose of the drug, a topical NSAID cream will expose only a small area to a very small dose."
If it receives FDA approval, the cream will be the first topical NSAID cream for horses available in this country that has been proven to be effective.