Aerosol pirbuterol: bronchodilator activity and side effects in ponies with recurrent airway obstruction (heaves).

This research article investigates the safety and effectiveness of aerosol pirbuterol as a bronchodilator in ponies suffering from recurrent airway obstruction (or ‘heaves’). It concludes that the drug has few undesirable side effects and is an effective treatment option.

Key Research Methods

• The study aimed to determine a safe dose of aerosol pirbuterol for administration to ponies. Observations for side effects such as sweating, trembling and excitement, along with measurements of heart and respiratory rates, were used during the cumulative administration of the drug to ascertain this dose. Initial adverse effects were observed after a 2,400 micrograms dose, intensifying at 3,200 micrograms. However, with a single administration of 3200 micrograms without prior lower doses, side effects were found to be minor.
• The chosen dose was then tested for its bronchodilator activity. This investigation was carried out on ponies that developed airway obstruction when they were housed in a barn and fed hay. Respiratory function measurements were made during clinical remission (Period A) and during an acute airway blockage (Period B).

Findings and Conclusion

• Pirbuterol had no effect on respiratory function during Period A.
• During Measurement Period B, the administration of pirbuterol significantly reduced pulmonary resistance as well as increasing dynamic compliance and minute ventilation.
• The benefits were noticeable as soon as 5 minutes after administering the drug and lasted for the 30 minute duration of the study. In contrast, the simulated drug (vehicle) had no effect on the respiratory function of the ponies.
• Consequently, the research concluded that aerosol pirbuterol could be administered safely to ponies and was an effective bronchodilator for those with recurrent airway obstruction, offering hope for better treatment options.