Aerosolized albuterol sulfate used as a bronchodilator in horses with recurrent airway obstruction.

OBJECTIVE

To determine the dose of aerosolized albuterol sulfate required to cause bronchodilation in horses with recurrent airway obstruction (RAO) and duration of this effect.

ANIMALS

19 horses with RAO (10 in experiment 1; 9 in experiment 2).

PROCEDURE

Horses were moved from pasture to stables, and airway obstruction was induced. Pulmonary function was measured in 10 horses before and 5, 10, and 30 minutes after administration of vehicle or 120, 240, 360, or 720 microg of the drug. Nine horses received vehicle or 360 or 720 microg of albuterol, and pulmonary function was measured at baseline and 5 minutes and 1, 2, 3, 4, 5, 6, and 7 hours later. Horses were evaluated for adverse drug effects.

RESULTS

360 microg of albuterol was required to cause significant bronchodilatation; 720 microg did not enhance bronchodilatation or increase duration of action. Depending on which pulmonary function parameter was evaluated, bronchodilatation achieved by use of albuterol lasted between 30 minutes and 1 hour. Because there was a significant vehicle effect, the combined effect of vehicle and drug lasted up to 3 hours. Adverse effects were not observed.

CONCLUSIONS

Aerosolized albuterol, 360 or 720 microg, is a safe and effective bronchodilator in horses with RAO. Onset of action is rapid (5 minutes), and effects last from 30 minutes to 3 hours.

CLINICAL RELEVANCE

Aerosolized albuterol is useful for treatment of bronchospasm in horses with RAO.