Dechra, a stride ahead in the treatment of navicular syndrome

Dechra Veterinary Products’ Osphos is a clodronate injection formulated to control the clinical signs associated with navicular syndrome in horses four years or older. Osphos is highly recommended for performance horses showing signs of lameness that can be attributed to navicular syndrome in particular thoroughbreds and quarter horses.  

Bone degeneration in the navicular bone is largely the root cause of pain and lameness detected in performance horses with the navicular disease. To combat this degeneration, the formulation for Osphos has been developed based on the first generation, non-nitrogenous bisphosphonates. The bisphosphonates have many positive effects including anti-inflammatory, anti-neoplastic, anti-resorptive and analgesic properties. The anti-resorptive properties are the key to encouraging a healthy bone remodelling process.  

In an adult horse, up to 10% of its skeleton is being re-modelled at any given time, working to repair micro damages resulting from mechanical stresses and to preserve the integrity and strength of the skeletal system. 

Once navicular syndrome is present, and has started to affect the navicular bone structures, an imbalance in the bone remodelling process can occur. The healthy process of osteoblasts forming bone and osteoclasts resorbing it is disrupted. This disruption can result in excessive navicular bone resorption and/ or abnormal mineralisation that can lead to more of the bone being dissolved than is replaced, weakening the bone structure over time.  

Osphos can be used to manage navicular syndrome as a result of the non-nitrogenous bisphosphonates. The main effect of the non-nitrogenous bisphosphonates is to decrease bone resorption and bring the balance of osteoclast and osteoblast activity back to normal by reducing the activity of the osteoclasts. The treatment of Osphos hinders bone resorption by binding to the bone minerals, and by exerting direct cellular effects on osteoclasts, it works to restore the natural balance.  

A clinical study has been conducted on Osphos and its effectiveness. The study ran across 56 days and tested 114 horses, with 86 horses treated with Osphos and the remaining 28 treated with saline. Of the 86 horses treated with Osphos, 68 of them (or 74.7%) saw a success rate and the controlled group reached 3% indicating the effectiveness of the product. 

Osphos was approved by the Australian Pesticides and Veterinary Medicines Authority (APVMA) in December 2016, and is only available to be purchased through licenced veterinarians.  

The dose rate for Osphos is 1.8mg/kg, up to a maximum dose of 900mg (15ml). It is an intramuscular injection, where the prescribed dose is split equally across three separate injection sites. Once the first dose has been administered, it can take up to two months to see the full effects of the bisphosphonates and a healthy re-modelling of the bone. Based on its effectiveness, a repeat dose can be administered three to six months after the initial dose to maintain soundness. 

For more information on Osphos, visit Dechra Veterinary Products; www.dechra.com.au