- Moderate to severe asthma (moderate asthma includes daily symptoms, daily use of inhaled short acting beta-agonist, exacerbations greater than 2 times per week that affect activity, and nighttime symptoms greater than once a week, FEV1 or Peak Flow PEF between 60 and 80 percent predicted and PEF variability greater than 30 percent; severe asthma includes continual symptoms, limited physical activity, frequent exacerbations together with frequent nighttime symptoms, FEV1 or PEF less than 60 percent predicted, and PEF variability greater than 30 percent)