Typically, people with allergies tend to complain about colds, coughs, watery eyes, sneezing and so on. Zyrtec is an allergy medicine that is prescribed for allergies and its related symptoms. Uses of Zyrtec Zyrtec is a drug that treats allergies caused by histamine. The two main components of Zyrtec are cetirizine hydrochloride and ephedrine. Histamine which induces the allergy symptoms such as sneezing, wh. . .