Phenoxybenzamine for the treatment of severe nonresponsive diarrhea in the horse.

The study investigates the use of the drug Phenoxybenzamine for treating severe cases of diarrhea in horses which haven’t responded to conventional treatments. It found that the drug was effective in most adult horses, but had mixed results in foals.

Methodology

• The researchers used a total of 18 horses in this study. Six of these were clinically normal, five had diarrhea induced for the experiment, and seven had naturally occurring diarrhea.
• Each horse was administered Phenoxybenzamine through an intravenous route. The dose was 2 mg of the drug per kilogram of the horse’s body weight. This dose was given in divided amounts.
• The researchers then monitored the effects of the drug on each horse.

Results

• The drug caused a blockage in the alpha adrenergic system of the healthy horses, which lasted around 72 hours. This effect was accompanied by tranquilization and mild constipation.
• During the trials with the horses with experimentally induced diarrhea (a part of an unrelated laminitis study), the severity of the diarrhea reduced following treatment with Phenoxybenzamine.
• In the group of horses with naturally occurring diarrhea, the treatment showed positive results in the adult horses but it wasn’t as effective with the foals. One foal did not respond to the treatment, whereas the other showed uncertain results.

Conclusion

• The researchers concluded that Phenoxybenzamine may be beneficial in treating cases of severe horse diarrhea which haven’t responded to traditional treatments.
• However, they stress further investigations are needed to fully understand why the drug works in this way, as the exact mechanism through which Phenoxybenzamine aids in alleviating diarrhea is not currently known.