Which medication is known as a potent antihistamine and can induce sedation?

Diphenhydramine is recognized as a potent antihistamine with notable sedative properties. This medication belongs to the first generation of antihistamines, which cross the blood-brain barrier more easily than newer agents, leading to its sedative effects. Diphenhydramine is often used to treat allergic reactions, motion sickness, and as a short-term sleep aid due to its ability to cause drowsiness.

In contrast, loratadine is a second-generation antihistamine designed to minimize sedation while providing relief from allergy symptoms. Corticosteroids are anti-inflammatory agents that do not primarily function as antihistamines and do not induce sedation. Epinephrine is a sympathomimetic drug used in emergency situations, such as anaphylaxis, and does not act as an antihistamine nor is it known for sedative properties. Therefore, diphenhydramine is correctly identified as both a potent antihistamine and a medication that can induce sedation.