It is also less convenient because it must be used three or four times daily.Cromolyn can be used to prevent symptoms before exposure to an asthma trigger or before exercising. (See Patient information: Exercise-induced asthma (Beyond the Basics).)Leukotriene modifiers ??? Leukotriene modifiers, such as montelukast (Singulair), zafirlukast (Accolate), or zileuton (Zyflo) are an alternative to in