Leukotriene pathway modifiers, also known as leukotriene blockers, are a relatively new type of asthma drug. The Food and Drug Administration approved Singulair (montelukast sodium), the first drug in this class, in 1998.

These medications, which can be taken in a once-a-day pill form, improve lung function by treating the underlying inflammation of asthma over the long term. These drugs are used for persistent cases of asthma and should be taken once a day, whether or not your child is experiencing asthma symptoms.