Inclusion criteria:

• Must be an outpatient.
• Age at second visit must be birth to <24 months old.
• Parent/guardian who is willing to sign, or has signed, an informed consent.
• Must have acute wheezing consistent with reversible obstructive airway disease.
• Must have an asthma symptoms score between 4-9 based on the TAL score (Modified Tal Asthma Symptoms Score measured by the study site) at Screening (Visit 1) while the subject is breathing room air.

Exclusion criteria:

• History of life-threatening asthma or wheezing that requires admission to an intensive care unit for treatment within 3 months prior to Screening, or he/she has been treated in the emergency room and admitted to the hospital for airways obstruction on two or more occasions within 3 months prior to Screening, or there is a history of intubation for respiratory distress due to airways obstruction.
• Has impending respiratory failure.
• Taken medications such as acute/chronic systemic corticosteroids, CNS stimulants, investigational medications, theophylline or aminophylline, anti-arrhythmic within a certain time period prior to the study.
• Having the following signs or symptoms: 1)present with fever (rectal temperature >100.5 ºF or tympanic temperature >101.5ºF); 2) present with known pulmonary (lung) and/or cardiac (heart) congenital malformations; 3) have an underlying chronic disease (respiratory (Chronic pulmonary disease includes congenital anomalies, bronchopulmonary dysplasia, and cystic fibrosis), cardiac, renal, or liver insufficiency, immunodeficiency, encephalopathy); 4) known or suspected foreign body aspiration; 5) their Modified Tal Asthma Symptoms Score is 10; 6) their weight is below a certain limit for the average for their age; 8) they were born before 34 weeks' gestation. 9) Laboratory tests for serum potassium and blood glucose within the following limits (potassium between 3.0-5.8 mEq/L and glucose between 45-140mg/dL).