Detailed Hydroxyzine dosage information for adults and children. Includes dosages for Anxiety, Nausea/Vomiting, Sedation and more; plus renal, liver and dialysis adjustments. Hydroxyzine, sold under the brand names Atarax and Vistaril among others, is an antihistamine medication. It is used in the treatment of itchiness, anxiety, insomnia, and nausea (including that due to motion sickness). Hydroxyzine is an antihistamine used to treat allergy symptoms and more. Learn how to use hydroxyzine for anxiety, its dosage, and potential side effects. Hydroxyzine is an antihistamine medication used to treat anxiety, tension, allergic skin reactions, nausea, vomiting, and to provide sedation before and after general anesthesia. It has also been used for pain, skeletal muscle relaxation, and certain bladder disorders. Hydroxyzine is used to help control anxiety and tension caused by nervous and emotional conditions. It can also be used to help control anxiety and produce sleep before surgery. Overview: Hydroxyzine is an antihistamine that is used for certain types of anxiety, itching due to allergic conditions, to help you relax before and after general anesthesia, or for nausea and. Hydroxyzine is an antihistamine with anticholinergic (drying) and sedative properties that is used to treat allergic reactions. Hydroxyzine is used for the relief of pruritus (itching) caused by various allergic conditions.