Primary Outcome Measures:
- comparison of the maximum percent fall in FEV1 after exercise challenge at the end of the 2-week treatment period between Arg/Arg and Gly/Gly patients [ Time Frame: 2 weeks ] [ Designated as safety issue: Yes ]
Secondary Outcome Measures:
- comparison of the maximum percent fall in FEV1 from pre-salmeterol baseline to the end of the 2-week treatment period between Arg/Arg and Gly/Gly subjects [ Time Frame: 2 weeks ] [ Designated as safety issue: Yes ]
- comparison of the maximum percent fall in FEV1 after 1st dose of salmeterol to the end of the 2-week treatment period between Arg/Arg and Gly/Gly subjects [ Time Frame: 2 weeks ] [ Designated as safety issue: Yes ]
Estimated Enrollment:
30
Study Start Date:
January 2008
Estimated Study Completion Date:
June 2009
Estimated Primary Completion Date:
February 2009 (Final data collection date for primary outcome measure)
In many patients with asthma, exercise-induced bronchoconstriction is a common and oftentimes limiting characteristic. Inhaled β2-adrenoreceptor agonists like albuterol are the most effective treatments available for the relief of acute asthma symptoms. However, there is evidence that regular use may lead to adverse effects in some patients. Previous studies have shown that polymorphisms of the β2-adrenergic receptor can influence airway responses to regular inhaled beta-agonist treatment.
Pharmacogenetics is the study of how genetic differences influence the variability in patients' responses to therapy, both therapeutic and adverse. Genetic susceptibility and environmental factors both play major roles in the etiology of asthma. The strong familial clustering of asthma has lead to a surge of research into the genetic predisposition of asthma. The aim of the present study is to utilize a double-blinded prospective cohort study to investigate whether genotype-specific effects occur when assessing the duration of protection conferred against exercise-induced bronchoconstriction by regular salmeterol treatment.