<qa>  What is the effect of zileuton on patients during an acute exacerbationThis acute bronchodilator effect may benefit patients during an acute exacerbation of asthma when added to the usual care in the ED or clinic setting. Critical Therapeutics has developed an injectable formulation of zileuton that will be explored for use in acute asthma exacerbations. This initial study is intended to provide PK data, information on safety and tolerability and some indication of pharmacologic activity as evidenced by lung function changes. In an attempt to enhance the potential for observing effects on lung function, only those patients with a demonstrated ability to respond by an increase in FEV1 of at least 10 within 3 hours after oral zileuton dosing will be enrolled. 