Montelukast sodium, the medicinal compound in Singulair, is a leukotriene inhibitor. Our body cells contain leukotrienes that, when activated by any allergen, bind to other cells, causing inflammation of the airway muscles and fluid accumulation in the lungs. Montelukast prevents the binding of some of leukotrienes, and is the top-selling medication for treatment of asthma and seasonal allergies [hay fever/rhinitis] in adults and children.
Montelukast cannot be used when asthma/rhinitis symptoms develop suddenly, or worsen; it takes anywhere between 3-14 days of the therapy to take proper effect, and it has to be taken as a combination medicine for asthma, with a fast-acting medicine/inhaler.
