Forty-two studies were included for the review: 20 randomised controlled trials (RCT, n=462 participants), 19 randomised controlled crossover trials (RCCT, n=238 participants), one open label clinical trial (n=15 participants), and two case studies (n=10 participants).
Asthma: In patients with acute asthma, nebulized furosemide was associated with a significant increase of 28.2% in forced expiratory volume in one second (FEV1, one RCT, n=40 patients) and a reduction in mean partial pressure of CO2 (one case study, n=7 patients), but there was no significant difference between furosemide and salbutamol (two RCTs, n=104 patients) or between furosemide and saline (one RCT, n=42 patients). Nebulized furosemide showed a protective action against the following bronchoconstrictive agents in experimentally induced asthma; adenosine 5'-monophosphate (p<0.01 and p<0.05; two RCTs n=20 participants), ultrasonically nebulized distilled water (p<0.01 to p<0.001; three RCTs, n=38 participants), sodium metabisulphite (p<0.05 to p<0.001; one RCT, four RCCTs, n=59 participants) and aspirin (no p-values reported; two RCCTs, n=22 participants). Furosemide also showed a protective action against exercise induced asthma (p<0.01; three RCTs and one RCCT, n=44 participants), allergen induced asthma (p<0.05; one RCT and one RCCT, n=21 participants), dry air (p<0.01; one RCCT, n=15 participants), and isocapnic hyperventilation (p<0.04 to p<0.002; three RCTs, n=30 participants). Results for the protective action of furosemide against methacholine were mixed.
Cancer: One open clinical trial of patients with cancer (n=15 patients) found significant reductions in sense of effort (p=0.013) and anxiety (p=0.04) with nebulized furosemide, but no significant differences in physiological measures. One case study of three cancer patients found that nebulized furosemide provided effective relief from dyspnoea where standard treatments had failed.
Chronic obstructive pulmonary disease (COPD): One RCCT (n=19 patients) found that nebulized furosemide significantly improved FEV1 (p=0.038) and subjective perception of dyspnoea (p=0.0140) in patients with COPD.
Healthy subjects: In healthy adults, nebulized furosemide protected against: cough induced by prostaglandin F2-alpha (p<0-.005; one RCCT, n=8 participants); methacholine induced bronchoconstriction (no p values reported; one RCT, n=22 participants); breath holding and resistive flow loading and hypercapnia-induced bronchoconstriction (p<0.05; one RCCT, n=12 participants). Four studies reported a small incidence of increased diuresis with nebulized furosemide.
Reported adverse events: Ten studies reported no adverse events.