As previous studies have suggested that inhaled furosemide may have a
protective effect against certain types of provocative challenges in a
sthmatic subjects, we investigated the role of furosemide in treating
acute asthma exacerbations. Twenty-four patients (n = 24) with acute a
sthma were entered into the study on presenting to the emergency depar
tment. They were blindly randomized to receive one of three drug regim
ens: (1) inhaled furosemide (40 mg) (n = 8); (2) inhaled metaprotereno
l (15 mg) (n = 7); or (3) the combination of furosemide (40 mg) and me
taproterenol (15 mg) (n = 9). We measured FEV(1) at entry (time 0) and
15, 30, 45, and 60 min after inhalation of the individual drugs or th
e combination from a face mask nebulizer. At entry, the three groups d
id not differ significantly in age (mean +/- SEM = 37.6 +/- 3.6, 38.5
+/- 3.6, and 41.0 years, respectively; p = 0.770), baseline FEV(1) (1.
01 +/- 0.27, 1.04 +/- 0.27, and 1.25 +/- 0.14 L, respectively; p = 0.6
20), or theophylline levels (2.87 +/- 1.8, 7.39 +/- 2.8, and 5.29 +/-
2.6 mu g/ml, respectively; p = 0.498). Pretreatment and posttreatment
potassium levels were similar among the three groups. Inhalation of fu
rosemide alone resulted in a 14.9 +/- 10.5 percent change in FEV(1) pe
rcent from baseline, which was not statistically significant. In contr
ast, metaproterenol alone resulted in a 42.9 +/- 15.2 percent increase
in FEV(1) percent (F ratio = 6.226; p = 0.0028). The combination of f
urosemide and metaproterenol resulted in a change in FEV(1) percent th
at was not statistically different compared with metaproterenol alone
(FEV(1) percent = 41.9 +/- 12 percent). No significant adverse effects
occurred in any of the groups.