Effects of acetylpromazine, xylazine, and vertical load on digital arterial blood flow in horses.

The research article describes a study that examined how different dosages of the drugs acetylpromazine and xylazine, as well as vertical load, affect blood flow in the arteries of horse hooves.

Methodology

• For the study, six conscious, standing horses were selected and perivascular ultrasonic flow probes were surgically implanted to monitor blood flow in the horses’ palmar digital arteries.
• Two different dosages of xylazine were administered to the horses: 0.55 mg/kg and 1.1 mg/kg of body weight. Three different dosages of acetylpromazine were also administered: 0.01 mg/kg, 0.02 mg/kg, and 0.04 mg/kg.
• Additionally, the effect of vertical load (the physical load or stress applied to the horse’s hoof when standing) on digital blood flow in the horses was also evaluated.

Findings

• After intravenous administration of xylazine, a significant and transient decrease in digital blood flow was observed in the horses. This indicates that the drug, under the studied conditions, reduces the amount of blood circulating in the hoof.
• Conversely, after intravenous administration of acetylpromazine, a significant and sustained increase in the blood flow was observed, implying that this drug can enhance blood circulation in the hoof under the tested conditions.
• A correlation between vertical load and digital blood flow was also found, though the study’s abstract does not elaborate on the nature of this correlation.

Implications

• Based on these findings, the authors suggest that acetylpromazine might serve as a useful treatment in clinical scenarios where horses are suffering from reduced blood flow in their hooves.
• On the other hand, xylazine may aggravate situations where there is already insufficient blood supply (ischemic conditions) in the hoof, suggesting the need for careful consideration when using it.