Used primarily as an antihistamine in nasal sprays and eye drops to relieve symptoms of allergic rhinitis and allergic conjunctivitis. It helps reduce sneezing, runny nose, nasal itching, and watery, itchy eyes by blocking histamine receptors and stabilizing mast cells to prevent the release of inflammatory substances. Also exhibits anti-inflammatory properties that contribute to its effectiveness in managing allergic responses. Some formulations are used to treat non-allergic vasomotor rhinitis. Available in both prescription and over-the-counter preparations.