Pranlukast hemihydrate is primarily used as a leukotriene receptor antagonist in the treatment of bronchial asthma and allergic rhinitis. It works by blocking the action of leukotrienes, which are substances in the body that cause inflammation, bronchoconstriction, and mucus production in the airways. By inhibiting these effects, it helps to reduce asthma symptoms such as wheezing, shortness of breath, and coughing. It is often prescribed for long-term management of asthma, particularly in patients who require regular treatment to control their symptoms. Additionally, it is used to prevent exercise-induced bronchoconstriction and to manage seasonal or perennial allergic rhinitis. The medication is typically administered orally and is suitable for both adults and children, depending on the formulation and dosage. It is important to note that it is not intended for the relief of acute asthma attacks, which require fast-acting bronchodilators.