Montelukast With Status Asthmaticus, Ages 2-5

Inclusion Criteria: * Participant's parent/legal guardian must give written informed consent prior to study participation. When appropriate, written assent from the child will also be obtained. * Participant, male or female, must be 2 to 5 years of age. * Participant must have a history of reactive airway disease (RAD) or asthma, and must currently be admitted for an acute exacerbation of RAD or asthma. * Primary physician must believe that patient would benefit from improved bronchodilation and improvement in clinical asthma severity score. * Participant must have received standard therapy for status asthmaticus: Oxygen as needed; 3 nebulized albuterol treatments of at least 2.5mg/dose; Methylprednisolone or prednisone loading dose of 2mg/kg; Ongoing methylprednisolone therapy @ 0.5mg/kg every 6 Exclusion Criteria: * Known hypersensitivity to montelukast * Chronic lung disease * Cardiac or pulmonary congenital anomalies * Known renal disease * Known hepatic disease * Known immunologic disorders other than allergy and atopy * Other explanations for respiratory distress * Use of leukotriene modifiers within 2 weeks of the acute presentation * Intubated patients