Studies on isoxsuprine hydrochloride for the treatment of navicular disease.

The research study focuses on the evaluation of isoxsuprine hydrochloride’s efficacy in treating navicular disease in horses. The researchers conducted clinical trials, monitored changes in blood counts, plasma biochemical parameters, and blood pressure, and assessed the peripheral vasodilatory action of the drug.

Conducting of Clinical Trials

• In the initial trial, 13 horses suffering from navicular disease were treated with the drug administered orally at a dose rate of 0.6 mg/kg body weight twice a day for periods extending from six to 14 weeks.
• Throughout the treatment, 12 horses fully recovered, despite two needing a 50% dose increase. Moreover, nine horses continued to see improvement two to 10 months after stopping the therapy.

Controlled Randomised Double Blind Clinical Trial

• The researchers also embarked on a controlled randomized double-blind clinical trial, where 16 horses suffering from navicular disease received treatment. They either received a placebo paste or the isoxsuprine paste for three weeks and were then re-examined.
• All the horses treated with isoxsuprine showed an improvement in gait, and seven out of eight horses became sound. Only two horses treated with a placebo paste showed slight improvement, and this difference was statistically significant (P less than 0.001).

Evaluating Physiological and Biochemical Effects

• To understand the physiological and biochemical impacts of isoxsuprine, the drug was administered to five Standardbred geldings at dose rates of 0.6 mg/kg bwt and 1.2 mg/kg bwt.
• Complete blood counts, routine plasma biochemical parameters, cardinal signs, and blood pressure measurements were performed up to 24 hours after a single dose, and no significant change was observed in any of these parameters.

Assessment of Vasodilatory Action

• The researchers assessed the peripheral vasodilatory action of isoxsuprine via infrared thermography of the lower limb performed before and up to 8 hours after administration to horses.
• They observed a significant increase in the distal limb temperature that occurred 90 to 480 mins after administering isoxsuprine. The maximum mean increase in distal limb temperature was 3.1 degrees Celsius and happened four hours after the drug’s administration.