Which of the following are examples of antihistamines?

Fexofenadine and Diphenhydramine are both examples of antihistamines, which are medications designed to block the action of histamine, a substance in the body that causes allergic symptoms.

Diphenhydramine is a first-generation antihistamine that is often used for the relief of allergy symptoms, as well as for its sedative properties. It works by crossing the blood-brain barrier, which is why it can cause drowsiness.

Fexofenadine, on the other hand, is a second-generation antihistamine that is less likely to cause sedation because it does not readily cross the blood-brain barrier. It is commonly used to treat hay fever and other allergies without the sedative effect associated with first-generation antihistamines.

Both of these medications function by inhibiting the effects of histamines in the body, thus providing relief from allergy symptoms such as sneezing, itching, and runny nose. This makes the choice containing these two drugs a clear representation of what antihistamines are and how they are used therapeutically.