Allergies Common Treatments Zyrtec Drug Warnings and Side Effects By Kristina Duda, RN Kristina Duda, RN Facebook LinkedIn Twitter Kristina Duda, BSN, RN, CPN, has been working in healthcare since 2002. She specializes in pediatrics and disease and infection prevention. Learn about our editorial process Updated on January 07, 2020 Medically reviewed Verywell Health articles are reviewed by board-certified physicians and healthcare professionals. Medical Reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Daniel More, MD Medically reviewed by Daniel More, MD Daniel More, MD, is a board-certified allergist and clinical immunologist. He is an assistant clinical professor at the University of California, San Francisco School of Medicine and currently practices at Central Coast Allergy and Asthma in Salinas, California. Learn about our Medical Review Board Print Zyrtec is an over-the-counter medication used to relieve symptoms of seasonal allergies such as itching, sneezing, and runny nose. Zyrtec is the brand name for the drug cetirizine. It is available for adults and children over 2 years old. Tetrabyte / Getty Images Active Ingredient Cetirizine Dosage and Directions Adults and children ages 6 to 64: One (10 mg) tablet every 24 hoursOne to two 5 mg chewable tablets every 24 hours depending on the severity of symptoms Children ages 2 to 6 years old and adults over age 65: One half (2.5 mg) to one (5 mg) teaspoon every 24 hours depending on the severity of symptoms Children under 2 years old: Ask a doctor Purpose Zyrtec is used to relieve symptoms of seasonal allergies, hay fever, and hives which include: Runny nose Sneezing Itchy eyes, nose or throat Itchy rash (hives) Taking Zyrtec for Allergies Side Effects Although most people don't experience significant side effects with this medicine, some may occur. Possible side effects of Zyrtec include: DrowsinessDry MouthIrritabilityLoss of sleepSore throatStomach painSwelling If any of these symptoms are severe or do not go away, contact your health care provider. Certain side effects can be very serious. If you have any of the following after taking Zyrtec or cetirizine, seek medical advice immediately. Symptoms of an allergic reaction such as hives, itching, skin rash, swelling of face, lips or tongueChanges in vision or hearingFast heartbeatHigh blood pressureInfectionTrouble urinating or change in the amount of urine Warnings If you have hives and experience difficulty breathing, significant swelling of the tongue or lips, wheezing, difficulty speaking or swallowing, dizziness, drooling, vomiting or loss of consciousness, seek emergency medical attention immediately. These are signs of a potentially life-threatening allergic reaction known as anaphylaxis. Ask a Doctor Before Using Zyrtec If you have any of the following conditions, ask your health care provider before using Zyrtec: You are allergic to Zyrtec, cetirizine, hydroxyzine, or any other medications.You have liver disease.You have kidney disease.You are pregnant, plan to become pregnant or are breastfeeding. Zyrtec is a great over the counter antihistamine and is generally very effective at relieving allergy symptoms. Some people try taking it for runny nose or congestion caused by colds and respiratory infections, but antihistamines typically don't work well against these illnesses. If you have never taken Zyrtec or an antihistamine before, be aware that it could make you drowsy. Don't take it for the first time if you need to drive or work before you know how it will affect you. This medicine is considered safe and effective for most people, but if you aren't sure or have questions about how it will work for you, talk to your health care provider before taking it. Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit 1 Source Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. De Sutter A, Saraswat A, van Driel M. Antihistamines for the common cold. Cochrane Database of Systematic Reviews. 2015. doi:10.1002/14651858.cd009345.pub2 Additional Reading "Zyrtec Products." McNeil - PPC, Inc. 2009.