Study of Daily Dosing With Levalbuterol, Racemic Albuterol, and Placebo in Pediatric Subjects With Asthma

Inclusion Criteria * Subject and subject's p/l guardian must be willing and able to comply with the study procedures and visit schedules * Subject, male or female, between the ages of 4 to 11 yrs * Female subjects 8 yrs or older will have a negative serum pregnancy test * Must have a documented diagnosis of asthma for a minimum of 6 months prior to study start * Must have stable baseline asthma and have been using a B-adrenergic agonist, and/or anti-asthma anti-inflammatory medication, and/or over-the-counter asthma medication for at least 6 mos. prior to study start * Must be in good health with the exception of reversible airways disease and not suffering from any chronic condition that might affect their respiratory function * Must have a chest X-ray that is not diagnostic of pneumonia, atelectasis, pulmonary fibrotic disease, pneumothorax, chronic obstructive pulmonary disease etc * Subject's p/l guardian must be able to complete the diary cards and medical event calendars reliably on a daily basis, understand dosing instructions and questionnaire completion, and demonstrate how to use the MiniWright PEF meter Exclusion Criteria * Female subject who is pregnant or lactating * Have participated in an investigational drug study within 30 days prior to study start, or who is currently participating in another clinical trial * Schedule prevents him or her from taking the first daily dose of study medication and/or starting study visits before 9 AM * Have travel commitments during the study that would interfere with trial measurements or compliance or both * Have a history of hospitalization for asthma within 60 days prior to study start, or who is scheduled for in-patient hospitalization, including elective surgery during the course of the trial * Have a known sensitivity to levalbuterol or racemic albuterol, or any of the excipients contained in any of these formulations * Subject using any prescription drug with which albuterol sulfate administration is contraindicated * Have currently diagnosed life-threatening asthma defined as a history of asthma episodes requiring intubation, associated with hypercapnia, respiratory arrest, or hypoxic seizures within 3 mos. prior to study start * Have a history of cancer * Subject with hyperthyroidism, diabetes, hypertension, cardiac diseases or seizure disorders that currently are not well controlled by medication or that may interfere with the successful completion of this protocol * Have a history of substance abuse or drug abuse within 12 months preceding V1 or a positive urine drug screening at study start * Have a documented history of bronchopulmonary aspergillosis or any form of allergic alveolitis * Has suffered from a clinically significant upper or lower respiratory tract infection in the 2 wks prior to study start * Have a history of cigarette smoking or use of any tobacco products * Subject who is a relative of a staff member