Should I Take Claritin, Zyrtec, or Allegra?

Which Antihistamine Is Best: Claritin, Zyrtec, or Allegra?

My patients frequently ask me which over-the-counter antihistamine they should take: Claritin (loratadine), Zyrtec (cetirizine), or Allegra (fexofenadine)? 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.

How Antihistamines Work

When you have been exposed to a substance you are allergic to (such as pet dander, ragweed, or peanuts), your body produces histamine, a chemical that is released into the bloodstream. Histamines cause the typical allergy symptoms of stuffy nose, watery eyes, and itchy throat that you associate with exposure to whichever allergens you are sensitive to. Antihistamines reduce the amount of histamines circulating in your system, thereby reducing symptoms. 

Advantages and Disadvantages of Claritin, Zyrtec, and Allegra

While Claritin, Zyrtec, and Allegra are all newer generation antihistamines with fewer symptoms than older antihistamines do, there may be some advantages for each of these 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. 

In addition, all may cause side effects such as:

  • Blurred vision
  • Confusion
  • Dry mouth
  • Drowsiness
  • Dizziness
  • Nausea and vomiting
  • Mood changes (mostly limited to some children)
  • Difficulty urinating 

Allegra is completely non-sedating (doesn't make people sleepy), while Claritin is minimally sedating (makes only a small number of people sleepy).

Zyrtec, on the other hand, 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 to start working.

Recommendations for Taking Claritin, Zyrtec, and Allegra

While you should consult your doctor about the best way to take any medication, there are widely accepted dosing recommendations for all three of these antihistamines. First and foremost, each work best when taken daily rather than intermittently. 

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:

Continue Reading