Second-generation antihistamines are medications used to relieve allergy symptoms, such as sneezing, runny nose, and itchy eyes. Unlike first-generation antihistamines, they are less likely to cause drowsiness because they do not easily cross the blood-brain barrier. Common examples include loratadine, cetirizine, and fexofenadine. These medications work by blocking the action of histamine, a substance in the body that triggers allergic reactions. Second-generation antihistamines are often preferred for long-term use due to their improved safety profile and reduced side effects compared to their first-generation counterparts.