The purpose of the study is to test how well 2 different medications stop asthma symptoms caused by exercising. The two medications that will be tested are "pretreatment with albuterol" and montelukast (Singulair®). Although both medications are used for treating asthma, we don't know which medicine is better at stopping asthma symptoms caused by exercising.

TThis is a randomized, crossover, placebo controlled trial of 30 patients, 7-17 years old with confirmed EIB. Patients will be randomized to montelukast treatment for at least 3 days or pretreatment with albuterol before an exercise challenge. Villiran and colleagues have shown that the protective effect of montelukast in treating EIB is apparent at day 3 of treatment and comparable to treatment for 4 and 8 weeks.

It is our hypothesis that pretreatment with albuterol will provide superior protection against breakthrough EIB in children with mild asthma compared to montelukast as maintenance therapy added to the current asthma regimen. Secondary aims of this study are to measure the effect of montelukast on leukotriene B4 (LTB4) concentrations as measured in EBC, and on inflammation measured by FeNO level. We hypothesize that since montelukast is a cysteinyl leukotriene receptor antagonist, patients with elevated concentration of LTB4 may have a greater response to this medication. Lastly, patients with elevated FeNO, a measure of airway inflammation respond differently to albuterol than montelukast his study is a randomized, double-blind, double-dummy, crossover clinical trial which will consist of 4 study visits and last up to 3 weeks.

Thirty children 7-17 years of age with asthma and EIB, regardless of current asthma therapy will be eligible for this trial. Patients will receive 3-7 days of therapy with either montelukast (5mg or 10 mg capsule) or placebo tablets. After 3-7 days of therapy the patients will be crossed over to receive the alternative therapy. Exercise challenges will be completed at screening, baseline, visit 3 and visit 4. All patients will have an albuterol metered-dose inhaler (MDI) to be used on an as needed basis for asthma symptoms.

Inclusion Criteria:

• Children 7-17 years of age
• Physician diagnosed asthma for at least 6 months
• EIB diagnosed by a positive exercise challenge at screening and baseline visits
• Forced expiratory volume in 1 second (FEV1) ≥ 70% of predicted at screening and baseline visit

Exclusion Criteria:

• History of cardiac dysfunction
• Unable to perform exercise challenge
• Use of montelukast