Cetirizine is a second-generation peripherally selective antihistamine used to treat allergic rhinitis (hay fever), dermatitis, urticaria (hives), and runny nose. [11]. It is taken by mouth. [12]. Effects generally begin within thirty minutes and last for about a day. [12]. 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. Learn about cetirizine (Zyrtec) usage and dosing. Read the latest news and reviews about the drug as well as potential side effects and popular alternatives. 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. Zyrtec Tablet is an antihistamine used to relieve allergy symptoms such as sneezing, runny or blocked nose, and itchy, watery eyes. It also helps reduce itching, hives, and skin reactions, including those from insect bites. Zyrtec (cetirizine hydrochloride) is an antihistamine that treats symptoms, such as itching, runny nose, watery eyes, and sneezing from hay fever (allergic rhinitis) and other allergies, such as allergies to molds and dust mites. Whether you need to know ZYRTEC ® dosages for adults or children, check out our dosing charts and FAQs for the ZYRTEC ® family of products, to find all the information you need. From the 1 doctor and allergist recommended OTC allergy brand when it comes to oral antihistamines, Zyrtec Tablets contain 10 mg of Cetirizine HCl to help relieve indoor and outdoor allergy symptoms caused by dust, pet dander, and pollen. Cetirizine (Zyrtec) is an antihistamine medication that treats allergy symptoms like itchy eyes, sneezing, a stuffy nose or hives. 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.