Should I Take Claritin, Zyrtec or Allegra?

Which Antihistamine is Best -- Claritin, Zyrtec or Allegra?

Woman looking at medication
Find out about over-the-counter antihistamines: Zyrtec, Claritin and Allegra.. BSIP/UIG/Universal Images Group/Getty Images

My patients frequently ask me which over-the-counter antihistamine they should take -- Claritin, Zyrtec or Allegra? All of these antihistamines have been available over the counter without a prescription for a number of years. But, if you're thinking these antihistamines are all the same -- well, they aren't. Depending on the allergic condition being treated, the age of the person, as well as other underlying issues (such as pregnancy), the best choice of antihistamine might be different.

So, instead of thinking that these medicines are all the same, learn more about each one of them and figure out which choice is the best for you.

There may be some advantages for each of these antihistamines over the others. For example, Claritin and Zyrtec are pregnancy category 'B', meaning they are preferred during pregnancy over Allegra. However, Allegra is considered to be safer for breastfeeding mothers compared to Zyrtec and Claritin. 

Allegra is completely non-sedating (doesn't make people sleepy), while Claritin is minimally sedating (makes only a small number of people sleepy) and Zyrtec causes sedation in approximately 1 in 6 people who take the medication.

Zyrtec and Allegra work quickly for the treatment of allergic rhinitis and hives -- typically within less than an hour, although studies show that Claritin takes many hours for it to start working. While all three of these antihistamines work for a full 24 hours when taken at recommended once daily dosages, Claritin and Allegra lose effectiveness after about 20 hours, while Zyrtec works well for a full 24 hours.

All of these antihistamines are indicated for adults and children 2 years of age and older, with Zyrtec and Claritin dosed once a day for all ages. Allegra is dosed twice a day for children age 2 to 11, and once a day for adults and children age 12 years and older.

While Claritin, Zyrtec and Allegra are all good antihistamines, there are some differences between them as outlined above which may make one of these antihistamines better than the others depending on a person's needs and characteristics.

Find out more about these antihistamines:

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