Zyrtec is an over-the-counter medication used to treat several allergy symptoms, including runny nose, sneezing, and itchy eyes. The drug is also used to treat itching due to hives. Some people take the drug year-round; others take it only during allergy season. Zyrtec comes in the form of tablets, chewable tablets, liquid-filled capsules, and syrup. Possible side effects include drowsiness, dry mouth, and fatigue.
Zyrtec® (cetirizine hydrochloride) is an antihistamine approved to treat the following allergy symptoms:
- Runny nose
- Itchy or watery eyes
- Itchy nose or throat.
It is also approved to treat itching due to hives, which may or may not be caused by allergies. The medication is also available in combination with a decongestant (see Zyrtec-D for more information). Although Zyrtec and Zyrtec-D were originally prescription products, they are now available without a prescription (see Zyrtec OTC).
Brand-name Zyrtec is made by McNeil Consumer Healthcare. Generic versions are made by various manufacturers.
Allergies occur when the body's immune system reacts to normally harmless substances that do not bother most people. This reaction is partly caused by the release of histamine from certain cells in the body. Zyrtec is an antihistamine, which means it blocks histamine from binding to histamine receptors and causing allergy symptoms. Since histamine is responsible for many of the symptoms of allergies, blocking it can be helpful. It is important to note that antihistamines do not help treat nasal congestion caused by allergies, since this symptom is not due to histamine.
Histamine is also responsible for the formation of hives (whether caused by allergies or not). Zyrtec also works to alleviate the itching due to hives by blocking histamine.