Onset of Efficacy of Montelukast in Seasonal Allergic Rhinitis

Montelukast has shown efficacy for seasonal allergic rhinitis (SAR); however, onset of action for SAR has not been presented. The aim of this study was to determine the onset of action of montelukast, 10 mg, measured in days after starting once-daily therapy, in spring and fall studies of SAR. Data were analyzed from four 2-week, double-blind, placebo-controlled phase III clinical trials. End points included the daytime nasal symptoms score, the nighttime symptoms score, the composite symptoms score (mean of the scores for daytime nasal symptoms and nighttime symptoms), and the daytime eye symptoms score. Using a 0 –3 scale (no symptoms to severe symptoms), daytime symptoms were rated by patients once daily each evening; nighttime symptoms were rated once daily each morning. Analyses of data pooled across the four evening dosing studies showed that montelukast, compared with placebo, produced significant improvement (p ≤ 0.001) from baseline by day 2 of treatment (after 2 doses) in the daytime nasal symptoms score, nighttime symptoms score, and composite symptoms score. Differences between montelukast and placebo for these end points in mean change from baseline at day 2 were −0.08 (95% CI, −0.12, −0.03), −0.08 (95% CI, −0.13, −0.04), and −0.08 (95% CI, −0.12, 0.04), respectively. These data represented a mean reduction for montelukast of 11–13% in symptom scores from baseline for each end point at day 2. When compared with the full 2-week response, these observed differences for each end point at day 2 (after 2 doses) represented a substantial proportion (over 70%) of the overall treatment benefits seen. Significant improvement (p ≤ 0.001) in the daytime eye symptoms score was seen by day 1 ( −0.08 [−0.12, −0.03]), after the first dose. In patients treated for SAR, montelukast has a beneficial effect on daytime and nighttime symptoms by the 2nd day of daily therapy.