To evaluate the effect of 12 weeks of therapy with montelukast 10 mg (Singulair) on exercise-induced asthma.
One hundred ten patients (15–45 years) were randomly assigned to montelukast 10 mg or placebo once daily for 12 weeks followed by a 2-week washout period.
Exercise challenges were performed at baseline and weeks 4, 8, 12, and 14. The data was analyzed with regard to the persistence of change in forced expiratory volume in 1 second (FEV1) over baseline for 60 minutes (area under the curve) and how quickly the FEV1 returned to within 5% of baseline. Methacholine challenges were performed at baseline and 12 weeks.
The average exercise-induced drop in FEV1 before randomization was 36 ± 12% for both groups with resting FEV1 83 ± 11%. The treatment group demonstrated a 47% reduction in area under the curve after exercise. The FEV1 dropped 22% in the treatment group compared with 32% drop in placebo group. The mean time required to return FEV1 to within 5% of the baseline was 44.3 minutes for the treatment group compared with 60.6 minutes in the placebo group. Approximately 25% of the montelukast patients had no protection with exercise challenge. There were no significant side effects and an equal number of patients from each group withdrew from the study.
Although exercise asthma was attenuated, the group mean change in FEV1 (22%) in the treated group was still consistent with a positive exercise challenge. Also, 25% of the patients had no protective effect in the exercise challenge. The efficacy of this class of drugs in mild to moderate asthma continues to be defined. Careful assessment of response as measured by symptom control and peak flow monitoring is necessary to assure the desired response has occurred.