HI Flow 4 MG is a medication containing montelukast, a drug commonly used to manage asthma and allergies. Montelukast is a leukotriene receptor antagonist that works by blocking the action of leukotrienes, which are chemicals in the body that cause inflammation, bronchoconstriction (tightening of the airways), and swelling in the lungs. By inhibiting these chemicals, HI Flow helps to reduce the symptoms of asthma, such as wheezing and shortness of breath, and is also used to prevent symptoms of seasonal allergies, like sneezing, itching, and runny nose. The 4 MG dose is often prescribed for children, as it is available in chewable tablet form, making it easier for younger patients to take. It may also be prescribed for chronic rhinosinusitis with nasal polyps or for exercise-induced bronchoconstriction in some cases.