text: Levocetirizine, sold under the brand name Xyzal, among others, is a second-generation antihistamine used for the treatment of allergic rhinitis (hay fever) and long-term hives of unclear cause. It is less sedating than older antihistamines. It is taken by mouth.
  Common side effects include sleepiness, dry mouth, cough, vomiting, and diarrhea. Use in pregnancy appears safe but has not been well studied and use when breastfeeding is of unclear safety. It is classified as a second-generation antihistamine and works by blocking histamine H-receptors.
  Levocetirizine was approved for medical use in the United States in 2007. It is available as a generic medication. In 2021, it was the 190th most commonly prescribed medication in the United States, with more than 2million prescriptions.