Hydroxyzine reduces activity in the central nervous system. It also acts as an antihistamine that reduces the effects of natural chemical histamine in the body. Histamine can produce symptoms of itching, or hives on the skin. Hydroxyzine is used as a sedative to treat anxiety and tension. It is also used together with other medications given during and after general anesthesia. Hydroxyzine is also used to treat allergic skin reactions such as hives or contact dermatitis.