Vistaril or Hydroxyzine is used primarily to treat itchiness caused by allergic reactions to any form of allergen.
It is an antihistamine and functions by blocking a naturally occurring substance in our bodies known as histamine; the production of which in the body is linked to symptoms of allergic reactions to unknown objects and bodies.
Vistaril may also be used for nausea and vomiting, or for allergic skin reactions such as hives breakout or contact dermatitis. It can be secondarily used short-term to treat anxiety and tension.
It is known to have sedative properties and thus, can be used to cause relaxation and sleepiness before surgeries and other similar medical procedures.