Study objectives: Salmeterol (S) and montelukast (M) individually inhibit the obstructive consequences of thermal stimuli such as exercise and hyperventilation (HV), but there is no information on whether these drugs can interact positively.
Design: Randomized trial.
Setting: University teaching hospital.
Participants: Atopic asthmatic patients with sensitivity to thermal provocations.
Interventions: Eleven asthmatic patients generated stimulus-response curves to isocapnic HV while breathing frigid air without any interventions and then after pretreatment with 42 μg of S, 10 mg of M, and the combination. The order of testing was randomly determined.
Measurements and results: Minute ventilation (V̇e) was increased in 20-L increments until FEV1 fell ≥ 15%. Measurements were obtained before and 1 h after drug administration, and then again 5 min after each bout of HV. In the nonintervention trial, the provocation commenced after the patients presented to the laboratory. In the control challenge, the mean (± SEM) FEV1 decreased 24.6 ± 1.7% from baseline. S and M both increased the mean prechallenge FEV1 significantly (S, 10.4 ± 1.7% [p < 0.01]; M, 4.1 ± 1.3% [p = 0.02]; S + M, p = 0.01). The combination of S + M produced greater bronchodilatation (mean improvement, 12.4 ± 2.3%) than M alone (p = 0.004), but not greater than S alone (p = 0.80). Both drugs blunted the obstructive response similarly (protection: M, 34.6 ± 15.1%; S, 60 ± 8.7%; p = 0.13). The benefits added arithmetically with the combined regimen (protection with S + M, 84.9 ± 5.5%; p = 0.01 vs S alone; p = 0.003 vs M alone).
Conclusion: These data indicate that the concurrent administration of single standard doses of S and M appears to provide greater protection against thermal stimuli than does either drug alone. Further experimentation will be required to ascertain whether the combination will provide additional clinical benefits to patients over those of the single agents.