A Randomized, Double-blind, Crossover study of the Effect of Inhaled Furosemide on Exertional Dyspnea and Lung Function Parameters in Patients with Chronic Obstructive Pulmonary Disease

BACKGROUND: Inhaled furosemide has shown promising results in the recent past in alleviation of dyspnea in healthy volunteers, terminally ill cancer patients and patients with chronic obstructive pulmonary disease (COPD). We studied the effect of inhaled furosemide in exertional dyspnea and its effect on different lung function parameters in patients with COPD. DESIGN: Randomized, double-blind, placebo controlled, crossover design. METHODS: Twenty two patients with moderate to severe COPD underwent spirometry and lung volumes testing before inhalation, 30 minutes (min), 1 hour and 6 hours after inhalation of furosemide or placebo on two days not more than a week apart. They performed single breath diffusion capacity (DLCO) test before and after 30 min of the inhalation of study drug. All the patients performed a 6 minute walk test (6mWT) after 30 min of study drug inhalation and rated dyspnea using Visual Analog Scale (VAS) at each minute during 6mWT. RESULTS: We found significant alleviation of dyspnea as shown by a lower mean VAS scores with furosemide compared to placebo (149.8 + 73.03 Vs 168.5 + 74.94; p = 0.009). There was a significant bronchodilation with furosemide as evident by the improvement in mean FEV1 and FVC. Inspiratory capacity also improved transiently with furosemide when compared to placebo indirectly showing a reduction in dynamic hyperinflation. We did not find a significant difference with Diffusion lung capacity. CONCLUSION: We conclude that inhaled furosemide alleviates the sensation of exertional dyspnea. It also causes a significant bronchodilation and reduces dynamic hyperinflation of lung which may have contributed in the alleviation of dyspnea