Inhaled diuretics attenuate acid-induced cough in children with asthma.

To evaluate the effect of inhaled diuretics, furosemide and amiloride, on cough induced by acid inhalation challenge in asthmatic children, a double-blind, randomized, placebo-controlled study was conducted. On separate days, 12 asthmatic children (10.3 +/- 0.7 [SEM] years) underwent acetic acid (AD) inhalation challenge after inhalation of furosemide (10 mg/m2 of body) amiloride (0.3 mg/m2 of body), or placebo (0.9% saline solution). Bronchoconstriction was not observed after administration of furosemide and amiloride. Both inhaled furosemide and amiloride exerted a protective effect against AA-induced cough in asthmatic children (p < 0.01 and p < 0.05, respectively), while there was little correlation between the individual protective potency of furosemide and amiloride against AA-induced cough (rs = 0.344, p = 0.255). These results demonstrate that both furosemide and amiloride can attenuate AA-induced cough, although, this protective effect of inhaled diuretics may not necessarily be dependent on Na(+)-K(+)-Cl- cotransporter or Na+ channel in airway epithelial cells.