Alcaftadine is a broad-spectrum antihistamine displaying a high affinity for histamine H1 and H2 receptors and a lower affinity for H4 receptors. It also exhibits modulatory action on immune cell recruitment and mast cell stabilizing effects. Alcaftadine is an inhibitor of the release of histamine from mast cells. Decreased chemotaxis and inhibition of eosinophil activation has also been demonstrated. LASTACAFT® (alcaftadine ophthalmic solution) indicated for the prevention of itching associated with allergic conjunctivitis.