It's used to treat anxiety and to ease itching from allergies. It's also used as a sleep aid (sedative) before and after general anesthesia. Hydroxyzine HCl (Atarax) comes as tablet and oral solution that are taken by mouth up to 4 times per day. Common side effects include sleepiness and dry mouth. 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 a prescription antihistamine used to treat anxiety and tension, itching from allergic skin conditions, and sedation before and after general anesthesia. It comes in three oral forms: There is also a hydroxyzine hydrochloride injection. 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. Hydroxyzine HCl prescription and dosage information for physicians and health care professionals. Pharmacology, adverse reactions, warnings, and Hydroxyzine HClside effects. Hydroxyzine is used for the short-term treatment of nervousness and tension that may occur with certain mental/mood disorders. Learn about side effects, drug interactions, dosages, warnings, and more. 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. What Is Hydroxyzine HCl? Hydroxyzine HCl is the hydrochloride salt of hydroxyzine, historically marketed as Atarax and widely available as tablets, oral solution, and solutions for intramuscular injection. Hydroxyzine, sold under the brand names Atarax (as hydrochloride) and Vistaril (as pamoate) 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 sold under the brand names Atarax or Vistaril. It is used as an antihistamine to help reduce the occurrence of sneezing or runny nose. Unlike some antihistamines you can use this drug to treat allergic reactions on the skin, such as hives or contact dermatitis.