Systemic morphine administration causes gastric distention and hyperphagia in healthy horses.

The study investigates the side effects of morphine, specifically its impacts on the size of the stomach and food intake, in healthy horses. By utilizing clinical and ultrasonographic examinations, the research found that morphine causes gastrointestinal depression, swells the stomach, and increases appetite in horses.

Objective and Methodology

• This experimental study was conducted to understand the impacts of morphine on the gastrointestinal system of horses. The team focused on changes in the stomach’s size and the animal’s food consumption. Morphine was administered systematically in healthy horses and their reactions were evaluated both through clinical and ultrasonography evaluations.
• The study was performed on six healthy French Trotter mares over three days. On the first day, clinical evaluations and abdominal ultrasonography were performed to record the baseline condition. This included measurements like the size of the stomach and the number of contractions per minute of different parts of the intestine.
• On the second day, morphine was injected at the dose of 0.1 mg/kg three times with a 4-hour gap. The same ultrasonographic evaluations were performed to monitor the effects of the drug. Amounts of hay and water intake, the frequency and weight of faeces were also recorded.
• On the third day, the horses underwent the same clinical and ultrasonographic evaluations as conducted on the first day to identify any significant changes post-morphine administration.

Results and Conclusions

• The results showed a decrease in the number of contractions in various parts of the horses’ intestines post morphine administration. The gastric size of the horses significantly increased due to a cumulative effect of repeated doses of morphine.
• Furthermore, the intake of hay and water was significantly increased, indicating a rise in the appetite (hyperphagia) of the horses.
• This study concluded that systematic administration of morphine in horses leads to gastrointestinal depression, causes the stomach to distend (expand), and provokes an increased appetite (hyperphagia).
• As the quantity of food given during morphine treatment needs to be monitored to avoid complications, the study suggests that horses receiving morphine should be closely observed for signs of gastric distention.
• The use of clinical and ultrasonographic examinations was identified as useful tools for monitoring the side effects of morphine administration in horses.
• This study, being conducted on healthy horses, highlights the need for further studies to evaluate these effects in clinically painful cases.