BACKGROUND. Cysteinyl leukotrienes are implicated in the inflammation of bronchiolitis. Recently, a specific cysteinyl leukotriene receptor antagonist, montelukast (Singulair [MSD, Haarlem, Netherlands]), has been approved for infants in granule sachets.
OBJECTIVE. Our goal was to evaluate the effect of montelukast on clinical progress and on cytokines in acute bronchiolitis.
METHODS. This was a randomized, placebo-controlled, double-blind, parallel-group study in 2 medical centers. Fifty-three infants (mean age: 3.8 ± 3.5 months) with a first episode of acute bronchiolitis were randomly assigned to receive either 4-mg montelukast sachets or placebo, every day, from hospital admission until discharge. The primary outcome was length of stay, and secondary outcomes included clinical severity score (maximum of 12) and changes in type 1 and 2 cytokine levels (including interleukin4/IFN-γ ratio as a surrogate for the T-helper 2/T-helper 1 ratio) in nasal lavage.
RESULTS. Both groups were comparable at baseline, and cytokine levels correlated positively with disease severity. There were neither differences in length of stay (4.63 ± 1.88 [placebo group] vs 4.65 ± 1.97 days [montelukast group]) nor in clinical severity score and cytokine levels between the 2 groups. No differences in interleukin 4/IFN-γ ratio between the 2 groups were seen. There was a slight tendency for infants in the montelukast group to recover more slowly than those in the placebo group (clinical severity score at discharge: 6.1 ± 2.4 vs 4.8 ± 2.2, respectively).
CONCLUSIONS. Montelukast did not improve the clinical course in acute bronchiolitis. No significant effect of montelukast on the T-helper 2/T-helper 1 cytokine ratio when given in the early acute phase could be demonstrated.