Montelukast is used to prevent and treat asthma in the long-term. It also helps relieve symptoms such as runny nose, stuffy nose and sneezing. Furthermore, montelukast is used to prevent asthma attacks in patients that are a result of exercise. This drug works by inhibiting the action of a substance called leukotriene that causes asthmatic and allergic symptoms.Montelukast sodium belongs to leukotriene receptor antagonists and comes in different forms of tablets; chewable, flash and granules which can be taken by mouth. Montelukast sodium, a CysLT1 antagonist, is usually taken once daily with or without food. Montelukast sodium is used in preventing the shortness and wheezing of breath caused by asthma and reduce the number of asthma attacks. Montelukast sodium is used before exercise to prevent breathing problems during exercise. Montelukast sodium can help in reducing the number of times you will need to use your rescue inhaler. Montelukast sodium is also used in relieving symptoms of allergic rhinitis and hay fever, such as sneezing and itchy nose. Montelukast sodium works by blocking the action of leukotriene D4 on the cysteinyl leukotriene receptor CysLT1 in the bronchial and lungs tubes by binding to it. Thus reduces the bronchoconstriction otherwise caused by the leukotriene and results in less inflammation. Montelukast sodium does not work right away and should not be used to treat sudden asthma attacks or other breathing problems.