Effects of furosemide on ponies with recurrent airway obstruction

The effect of aerosol and intravenous administrations of furosemide was examined in ponies with recurrent obstructive pulmonary disease, commonly called 'heaves'. This recurrent airway disease bears many similarities to human asthma. Six ponies with the disease (principal animals) were studied during clinical remission and during an acute attack of airway obstruction precipitated by stabling and feeding dusty hay. Six control animals were also studied. Furosemide (1.0 mg/kg) or vehicle was administered by aerosol in the first study, and intravenously in a second study. In principal ponies with airway obstruction, furosemide administration significantly decreased pulmonary resistance and increased dynamic compliance, but had no effect on PaO2 or PaCO2. The time course and magnitude of lung function changes were similar following aerosol or intravenous drug administration. Vehicle was without effect in both groups of animals at all time periods and furosemide had no effect in controls or in principals in clinical remission.