Antihistamines are used to treat symptoms of allergies and hives. They also have other uses, such as managing motion sickness and helping with short-term sleep difficulties. Antihistamines work by blocking histamine, a substance in your body that causes allergic symptoms like itching, sneezing, and runny nose. Some antihistamines are known to cause drowsiness, while others are nondrowsy. These medications come in different forms, including oral pills, liquids, and nasal sprays. Examples include cetirizine (Zyrtec), loratadine (Claritin, Alavert), diphenhydramine (Benadryl, ZzzQuil), and hydroxyzine pamoate (Vistaril).
