Conditions: Asthma
Keywords: asthma exercise induced asthma exercise induced bronchoconstriction long acting beta agonist salmeterol exercise challenge bronchoprotection beta 2 adrenergic receptor polymorphisms pharmacogenetics
Allocation: NON_RANDOMIZED | Intervention model: PARALLEL
Enrollment: 30
Healthy volunteers: no

Brief summary:
The purpose of the study is to find out how well a long-acting beta agonist like salmeterol works in people with different forms of the same gene. Our hypothesis is that asthmatics with the Arg/Arg genotype will have loss of bronchoprotection against exercise-induced asthma with regular salmeterol treatment, as compared to asthmatics with the Gly/Gly genotype.

Detailed description:
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.

Arms:
arm 1: Arg/Arg subjects on 2 week salmeterol treatment arm 2: Gly/Gly subjects on 2 week salmeterol treatment

Interventions: intervention 1: salmeterol
Intervention descriptions: intervention 1: salmeterol 50 micrograms twice daily for 2 weeks

Protocol document: