Injectable Osteoarthritis Medication Approved By FDA

The U.S. Food and Drug Administration has approved a pentosan polyuslfate sodium intramuscular injection for horses to control clinical signs associated with osteoarthritis. The product, sold under the name of Zycosan, is the first injectable pentosan product to be granted FDA approval.

Horses suffering from osteoarthritis may be lame, stiff, or experience joint swelling. There is no cure for the breakdown of joint cartilage, but management changes can help control the disease and improve the affected horse's quality of life.

Non-FDA approved injectable formulations of pentosan have long been used in horses. FDA approval means that the product has met the FDA's rigorous standards and that the drug is effective for its intended use. Approval also means that the drug has been consistently manufactured for strength, purity and identity. The FDA encourages veterinarians to use FDA-approved Zycosan when pentosan use is indicated.

Zycosan efficacy was tested in a field study involving lame, client-owned horses that had been diagnosed with osteoarthritis in one leg. The horses were separated into two groups: one that received a Zycosan injection in the neck once a week for four weeks (for a total of four doses), and horses that received equal doses of saline at the same protocol.

Each horse's lameness was graded on days 0 and 28. On day 28, more horses in the Zycosan treated group had improved lameness compared to the control group. Study results indicate that Zycosan treatment, used at the labeled dose, benefits horses with single-limb lameness caused by osteoarthritis.

The most-common adverse reactions were injection site reactions and prolonged coagulation time. Reactions that occurred at time of dosing were resolved; other reactions were delayed up to three days after injection, but resolved within five days and the majority didn't require treatment.

Zycosan is available by prescription only.