EFFECTS OF INHALED BECLOMETHASONE DIPROPIONATE ON RESPIRATORY-FUNCTION IN HORSES WITH CHRONIC OBSTRUCTIVE PULMONARY-DISEASE (COPD)

The effects of beclomethasone dipropionate on pulmonary function and a rterial blood gas values were investigated in horses with chronic obst ructive pulmonary disease (COPD). Six mature mares, diagnosed as havin g COPD based on clinical signs, cytological examination of bronchoalve olar lavage and pulmonary function testing, were used. Beclomethasone dipropionate (3750 mu g) was administered b.i.d. for a 2 week period w ith a metered dose inhaler using a mask. Pulmonary function tests and arterial blood gas analyses were performed at weekly intervals, starti ng before beclomethasone administration and for 4 weeks thereafter. Up per airway endoscopy and nasopharyngeal fungal cultures were performed before and after treatment. Maximal variations in transpulmonary pres sure (Delta PL) were elevated in all horses at baseline. Beclomethason e administration resulted in a significant decrease in Delta PL in 5 h orses, and Delta PL fell to within the normal range in 4 horses. Two w eeks after the end of treatment, Delta PL was at or above baseline val ues in all horses. Total pulmonary resistance and elastance decreased significantly during treatment and returned to or above baseline value s after the administration of beclomethasone was discontinued. At base line, PaO2 range was 53-90 mmHg. In 4 horses with pronounced laboured breathing, PaO2 increased with treatment. One horse became reluctant t o inhale the beclomethasone after one week, and only a transient impro vement in respiratory function was noted in this animal. One horse dev eloped a mild lower airway infection 24 h after the beginning of treat ment, but no other possible side effects were noticed. pharyngeal fung al cultures were negative before and after treatment. It can be conclu ded from the results of this study that inhaled beclomethasone dipropi onate causes a marked improvement of respiratory function in horses wi th COPD.