Claritin vs. Zyrtec
Zyrtec and Claritin are approved for similar uses. Both are approved to treat allergy symptoms and to treat chronic hives of unknown cause (known as chronic idiopathic uticaria). Zyrtec is also approved for year-round allergies and household allergies (such as allergies to dust mites).
Depending on the particular form, both Zyrtec and Claritin are approved for use in children as young as two years old (Zyrtec in the syrup form and Claritin in the syrup or chewable tablet form).
Some studies suggest that Zyrtec (versus Claritin) may be more effective as an antihistamine. However, it is not clear if these differences are large enough to be noticeable.
Most importantly, different people react in different ways to medications. One person may find Claritin to be much more effective, while the next person may discover that Zyrtec is more effective. In the area of nonsedating antihistamines, people usually form strong preferences toward or against certain medications.
Drowsiness is the most important difference between these two medications, in terms of side effects. Even though Zyrtec is often classified as a nonsedating antihistamine, it is generally accepted that Zyrtec is more likely to cause drowsiness, compared to the other nonsedating antihistamines (including Claritin).
However, there is a wide variety of individual responses to these medications. Some people will experience more drowsiness while taking Zyrtec, while others may notice more problems with drowsiness while taking Claritin.
Although the nonsedating antihistamines are all very similar, some people may find that one works better than the others. With nonsedating antihistamines, "trial and error" is usually the way to determine which medication works best for you.