The effects of
beclomethasone dipropionate on pulmonary function and arterial blood gas values were investigated in horses with
chronic obstructive pulmonary disease (
COPD). Six mature mares, diagnosed as having
COPD based on clinical signs, cytological examination of bronchoalveolar lavage and pulmonary function testing, were used.
Beclomethasone dipropionate (3750 microg) was administered b.i.d. for a 2 week period with a
metered dose inhaler using a mask. Pulmonary function tests and arterial blood gas analyses were performed at weekly intervals, starting before
beclomethasone administration and for 4 weeks thereafter. Upper airway endoscopy and nasopharyngeal fungal cultures were performed before and
after treatment. Maximal variations in transpulmonary pressure (deltaPL) were elevated in all horses at baseline.
Beclomethasone administration resulted in a significant decrease in deltaPL in 5 horses, and deltaPL fell to within the normal range in 4 horses. Two weeks after the end of treatment, deltaPL was at or above baseline values in all horses. Total pulmonary resistance and elastance decreased significantly during treatment and returned to or above baseline values after the administration of
beclomethasone was discontinued. At baseline, PaO2 range was 53-90 mmHg. In 4 horses with pronounced laboured breathing, PaO2 increased with treatment. One horse became reluctant to inhale the
beclomethasone after one week, and only a transient improvement in respiratory function was noted in this animal. One horse developed a mild lower airway
infection 24 h after the beginning of treatment, but no other possible side effects were noticed. Pharyngeal fungal cultures were negative before and
after treatment. It can be concluded from the results of this study that inhaled
beclomethasone dipropionate causes a marked improvement of respiratory function in horses with
COPD.