Which of the following is a dual-action medication that combines antihistamine and mast cell stabilization properties?

Olopatadine is recognized as a dual-action medication because it possesses both antihistamine and mast cell stabilization properties. As an antihistamine, it effectively blocks the H1 receptors, alleviating allergic symptoms such as itching, redness, and swelling by preventing the action of histamine released during an allergic reaction. Additionally, olopatadine stabilizes mast cells, thereby inhibiting the release of further inflammatory mediators, which contributes to its overall therapeutic efficacy in treating allergic conjunctivitis. This combination of actions allows for both immediate relief of symptoms and a reduction in the frequency and severity of subsequent allergic responses.

Emedastine, on the other hand, primarily operates as an H1 receptor antagonist without notable mast cell stabilizing effects. Cromolyn sodium and lodoxamide are primarily mast cell stabilizers and do not possess significant antihistamine activity. Hence, their use is generally more focused on the prevention of allergic responses rather than immediate symptomatic relief. Olopatadine's unique combination of properties makes it particularly effective for managing allergic conditions in the ocular context.