Ketotifen fumarate is primarily used as an antihistamine and mast cell stabilizer, making it effective in treating allergic conditions. It is commonly prescribed for the management of allergic conjunctivitis, where it helps reduce itching, redness, and swelling in the eyes. Additionally, it is used in the treatment of asthma, particularly in preventing allergic asthma attacks by inhibiting the release of histamine and other inflammatory mediators from mast cells. In some cases, it is also utilized to alleviate symptoms of chronic urticaria (hives) and other allergic skin conditions. Its dual action of blocking histamine receptors and stabilizing mast cells makes it a versatile option for long-term allergy management.