Study of Levalbuterol and Racemic Albuterol in Pediatric Subjects With Reactive Airways Disease (RAD)

Inclusion Criteria: * Subject, male or female, must be between the ages of birth to 48 months inclusive at the time of consent. * Subject must have experienced at least one previous episode or have a history of reactive airways disease. * Subject must have an Oxygen saturation ≥ 90% at room air or with no more than 2 L/min supplemental Oxygen. Exclusion Criteria: * Subject who has participated in an investigational drug study within 30 days prior to study start, or who has previously participated in this study. * Subject with a known sensitivity to levalbuterol or racemic albuterol, including Ventolin® or any of the excipients contained in any of these formulations. * Subject using any prescription drug with which levalbuterol or racemic albuterol sulfate administration is contraindicated.