Vistaril (hydroxyzine) is an antihistamine that is also FDA-approved for the treatment of anxiety. It works by calming activity in the central nervous system, which can help reduce feelings of tension and anxiety. Because it acts fairly quickly and is not addictive, it is sometimes used as a short-term or as-needed option for anxiety symptoms. A common side effect is drowsiness, which can actually be helpful for patients whose anxiety also interferes with sleep. It is generally used for temporary symptom relief rather than long-term anxiety management.