Montelukast sodium salt is primarily used in the treatment of asthma and allergic rhinitis. It works by blocking leukotrienes, which are substances in the body that cause inflammation, tightening of airway muscles, and production of excess mucus. By inhibiting these effects, it helps to prevent asthma attacks and reduce symptoms such as wheezing, coughing, and shortness of breath. Additionally, it is effective in managing seasonal allergies, providing relief from symptoms like sneezing, nasal congestion, and itchy or runny nose. It is often prescribed as a long-term maintenance medication rather than for immediate relief during an acute asthma attack. Montelukast sodium salt is also used to prevent exercise-induced bronchoconstriction, making it beneficial for individuals who experience asthma symptoms triggered by physical activity.