Zyrtec Prescription is a FDA approved allergy medication. Zyrtec Cetirizine is an antihistamine used to treat severe allergies. Zyrtec Prescription combines prescription allergy medication with a secure online ordering system allowing you to purchase Zyrtec Prescription Medication and other allergy medicine securely online. Customer service associates are available to answer questions you have about buying Zyrtec or allergy medication online.