Help reduce hives and relieve uncomfortable hive-related itching with ZYRTEC® 24 Hour Hives Relief Tablets. Each antihistamine tablet is formulated with 10 mg of cetirizine hydrochloride to help reduce hives and relieve itching due to hives (urticaria). These antihistamine tablets start to work fast to reduce hives and relieve hive-related itching in under 45 minutes. Pack a bottle of ZYRTEC® Hives Relief medicine in your bag to help relieve hive related itching and reduce hives while on the go. Choose ZYRTEC®, the #1 doctor and allergist-recommended brand among OTC oral antihistamines.