Montelukast

Montelukast (Singulair) is a leukotriene (loo-koe-TRY-een) inhibitor. Leukotrienes are chemicals your body releases when you breathe in an allergen (such as pollen). These chemicals cause swelling in your lungs and tightening of the muscles around your airways, which can result in asthma symptoms.

Montelukast is used to prevent asthma attacks in adults and children as young as 12 months old. Montelukast is also used to prevent exercise-induced bronchoconstriction (narrowing of the air passages in the lungs) in adults and children who are at least 6 years old.

Montelukast is also used to treat symptoms of year-round (perennial) allergies in adults and children who are at least 6 months old. It is also used to treat symptoms of seasonal allergies in adults and children who are at least 2 years old. Montelukast is used for allergies, only after other treatments have failed. If you already take montelukast to prevent asthma or allergy symptoms, do not use an extra dose to treat exercise-induced bronchoconstriction.