by Dr Scot Plummer, Brisbane Pet Surgery, QLD
Zydax contains pentosan polysulfate and is used to treat osteoarthritis in dogs. It’s a very effective drug.
What’s good about it
There are two situations where we commonly use Zydax. It’s effective with dogs that already have arthritis and are suffering from cartilage loss. It helps look after their joints even if they suffer from medially luxating patellas. It’s also very effective with old dogs with arthritis in their stifles, elbows or backs. Zydax improves the condition of the joint rather than just stopping the inflammation and pain.
Studies have suggested that pentosan polysulfate stimulates STEM cells in the joint and improves cartilage. It has been shown that the drug acts on the subchondral bone. Bone oedema between three and 30 millimetres disappear after a six-week treatment with the drug.
Pentosan polysulfate stops the release of the inflammatory mediators from missing inflamed bone. Recently, a published paper showed that it stopped the release of nerve growth factor (NGF) from inflamed bone cells. NGF stimulates more nerves and creates more pain.
We have had outstanding results using Zydax. I had one case where an old dog was practically immobile but after 14 injections of Zydax over 17 weeks, he could walk up stairs again.
We use Zydax proactively because no matter what technique we use to treat a torn cruciate ligament, within two or three years most of the dogs start to get arthritis. If we stop the inflammation, we don’t see arthritis in the long term.
What’s not so good
The only negative is that Zydax is a weak anticoagulant. In humans, it’s been reported that there can be bruising after it’s injected under the skin but we don’t see that in dogs.