Evaluation of the Effect of Levalbuterol on Allergen Induced Airway Inflammation In Subjects With Atopic Asthma

Overview

The most commonly used drug for immediate relief of symptoms of asthma is the blue puffer, albuterol or salbutamol (Ventolin). Racemic albuterol is a mixture of two forms of albuterol which are mirror images of each other i.e. R-and S- isomers. The investigational treatments are R-albuterol and S-albuterol. R-albuterol ( levalbuterol) has been shown to have a slightly better bronchodilator effect as compared to the racemic albuterol and is well- tolerated in patients. However it is still not clear whether the S-isomer has no effect or has a harmful effect on the airways. The purpose of this study is to compare the effects of the R- and S- isomers on allergen induced airway inflammation in subjects with mild atopic asthma. This will give us a better idea as to whether the routine use of levalbuterol is superior to racemic albuterol.

The most commonly used drug for immediate relief of symptoms of asthma is the blue puffer, albuterol or salbutamol (Ventolin). Racemic albuterol is a mixture of two forms of albuterol which are mirror images of each other i.e. R-and S- isomers. The investigational treatments are R-albuterol and S-albuterol . R-albuterol ( levalbuterol) relieves the narrowing of the bronchial air passages in the lungs and has been approved by the U.S. FDA, but is not currently licensed for use in Canada. We have obtained approval from Health Canada to use these isomers for the purpose of this study. R-albuterol has been shown to have a slightly better bronchodilator effect as compared to the racemic albuterol and is well- tolerated in patients, with only a few mild to moderate side effects (such as palpitations, diarrhoea, abdominal pain, bodyache, leg cramps and headache). However it is still not clear whether the S-isomer has no effect or has a harmful effect on the airways. The purpose of this study is to determine the effect of this drug, levalbuterol, on the allergen-induced inflammatory response in adult subjects with asthma. Specifically, we want to look for changes in airway eosinophils by examining sputum samples and to compare the effects of the R- and S- isomers on airway inflammation. This will help us to understand whether the racemic albuterol could worsen inflammation because of the presence of the S-isomer, and this will give us a better idea as to whether the routine use of levalbuterol is superior to racemic albuterol.