Effects of domperidone on digital laminar microvascular blood flow in clinically normal adult horses.

The research studies the effects of two drugs, domperidone and acepromazine maleate, on blood flow in the podotheca, or “hooves,” of healthy adult horses. Results suggest that domperidone potentially helps prevent blood vessel restriction and decreased hoof blood flow in horses with a common hoof disease called laminitis.

Methods and Procedures

• The researchers conducted a 4-phase crossover study with eight clinically healthy adult horses, consisting of 4 mares and 4 geldings.
• Domperidone was given both orally (at two different dosages of 1.1 mg/kg and 5.5 mg/kg) and intravenously (at a dose of 0.2 mg/kg). As a comparison group, acepromazine was administered intravenously at a dose of 0.04 mg/kg.
• After each treatment, a washout period of one week was implemented, allowing the drugs to exit the horses’ systems prior to the next drug administration.
• Laser Doppler flowmetry, a technique used to measure blood flow, was employed to obtain measurements of laminar microvascular blood flow (LMBF), which is the blood flow in the laminae or thin layers of the horses’ hooves.
• Data was collected at various time intervals pre- and post-drug administration. The percentage change from the baseline blood flow for each treatment was then calculated.

Findings of the Study

• The oral administration of domperidone at both 1.1 mg/kg and 5.5 mg/kg doses significantly increased the LMBF starting 4 hours post-administration and this uptick persisted for at least 8 hours.
• The intravenous administration of domperidone at a dose of 0.2 mg/kg also notably increased LMBF at 10 and 12 hours after administration.
• Injection of acepromazine (0.04 mg/kg, IV) led to a significant increase in LMBF at 3, 5, 8, and 10 hours post-administration.
• No negative effects from the drugs were detected in any of the horses involved in the study.

Conclusions Drawn

• The study concludes that domperidone may be beneficial in preventing vasoconstriction, which is the narrowing of blood vessels, and a reduction in hoof blood flow that is often seen in horses suffering from laminitis.
• However, the researchers acknowledge the need for further investigation into the effects of domperidone on horses suffering from laminitis, indicating that this research provides an initial understanding, but not a complete scenario.