Overview: Cetirizine is an antihistamine that is taken to help treat allergy symptoms, such as a runny nose, itchy or watery eyes, sneezing, or an itchy nose or throat. It may also be used to. Is ZYRTEC® an antihistamine? Yes. ZYRTEC ® contains cetirizine HCl, which is an antihistamine. Explore ZYRTEC® allergy medicine products for adults. Made with Cetirizine HCl, our adult antihistamine products provide fast & effective allergy treatment. Cetirizine is a second-generation peripherally selective antihistamine used to treat allergic rhinitis (hay fever), dermatitis, urticaria (hives), and runny nose. [11] Zyrtec is an antihistamine used to treat hives and seasonal allergies. Common side effects of Zyrtec include sedation, fatigue, and dizziness. Zyrtec is available for use by children 2 years and older and adults. Cetirizine is a second generation antihistamine that reduces the natural chemical histamine in the body. Histamine can produce symptoms of sneezing, itching, watery eyes, and runny nose. Cetirizine is used to treat cold or allergy symptoms such as sneezing, itching, watery eyes, or runny nose. Learn how this drug works, what it’s used for, and how to take it safely. If you have year-round allergies, or seasonal allergies like hay fever, your doctor may recommend cetirizine. Cetirizine. Cetirizine (Zyrtec) is a second-generation antihistamine. It blocks histamine, a natural chemical in your body that can cause allergy symptoms like itchiness, itchy eyes, or runny nose. Zyrtec (cetirizine) is an over-the-counter antihistamine used to relieve allergy symptoms, including sneezing, itching, watery eyes, and a runny nose, and also reduces hives (urticaria). Zyrtec is usually taken once a day. Cetirizine (Zyrtec) is an antihistamine medication that treats allergy symptoms like itchy eyes, sneezing, a stuffy nose or hives.