It treats and prevents symptoms of allergies like itchy eyes, sneezing and hives. It works by blocking histamine in your body. A common brand name of this medication is Allegra®.

Studies point to Claritin being more effective than Allegra for allergic rhinitis (faster onset of action, more symptom relief) Allegra may provide more eye symptom relief. Studies suggest Allegra may be more effective than Claritin for wheal and flare reactions (an allergic skin reaction).

When comparing Allegra, Zyrtec, and Claritin, remember that: Allegra is less likely to make you drowsy. Zyrtec and Allegra work faster than Claritin. All three work well to treat hives and symptoms of hay fever, such as itchy skin and eyes and post-nasal drip.

The main active ingredient in Allegra is fexofenadine. The main active ingredient in Zyrtec is cetirizine. Both of these drugs are antihistamines. Antihistamines work by blocking a substance called histamine in your body.

Newer antihistamines like Allegra and Claritin are generally safe for daily use. But allergy medications with decongestants, such as Claritin-D or Benadryl-D, could make your allergies worse with long-term use.

Several studies have found cetirizine (Zyrtec) to be more effective than fexofenadine (Allegra) at relieving symptoms of allergic rhinitis and urticaria, and it appears to have a longer duration of action.

The choice between Allegra and Claritin depends on several factors. Allegra can be used by patients as young as 6 months, and you do not need to adjust the dose if you have liver problems. However, Claritin has fewer drug interactions than Allegra, and it is a safer choice if you are pregnant.

Allegra works within two hours and Zyrtec works within one hour. Several studies have found cetirizine (Zyrtec) to be more effective than fexofenadine (Allegra) at relieving symptoms of allergic rhinitis and urticaria, and it appears to have a longer duration of action.

Allegra can be used by patients as young as 6 months, and you do not need to adjust the dose if you have liver problems. However, Claritin has fewer drug interactions than Allegra, and it is a safer choice if you are pregnant.

Both Allegra and Zyrtec are effective at treating allergy symptoms and take a similar amount of time to start working. However, some studies have found that Zyrtec's beneficial effects last longer than those of Allegra.

Cetirizine, a metabolite of hydroxyzine, is an antihistamine with as distinguishing features: 1) exquisite anti-H1 specificity: cetirizine appears unique in being devoid of action on receptors other than the H1 receptor; 2) potency: at unit dose it is the most potent antihistamine in the skin and the lung; 3) absence ...

What side effects may I notice from receiving this medication? Side effects that you should report to your care team as soon as possible: Allergic reactions or angioedema - skin rash, itching, hives, swelling of the face, eyes, lips, tongue, arms, or legs, trouble swallowing or breathing.