Comparison of add-on therapy to inhaled fluticasone propionate in children with asthma: residual volume and exhaled nitric oxide as outcome measures.

The purpose of this study was to evaluate changes in lung function and fractional exhaled nitric oxide (FeNO) in children with mild to moderate persistent asthma treated with low-dose inhaled steroids but still manifesting significantly increased residual volume (RV). This was a crossover study evaluating lung function and FeNO before and after a 2-week crossover therapy period by adding either montelukast or salmeterol to inhaled fluticasone propionate in 12 children with asthma. Salmeterol increased forced expiratory volume at 1 second (FEV(1)) and decreased RV without effects on eNO. Addition of montelukast produced a statistically significant decrease both for RV (from 191.7 +/- 60.8% to 132.4 +/- 36.1%; p = 0.03) and for eNO (from 14.0 +/- 6.3 ppb to 8. 5+/- 5.0 ppb; p < 0.01). No effect was observed for the montelukast treatment period in FEV(1) and forced expiratory flow at 25-75%. Add-on therapy may reduce RV and decrease levels of FeNO, leading to consideration of a possible anti-inflammatory additive effect that could improve the control of the disease.