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Drug vs. Drug

Allegra vs. Zyrtec: Differences, similarities, and which one is better for you

Allegra and Zyrtec are popular OTC antihistamines for allergies. Learn about their differences, side effects, and interactions to make the best choice for allergy relief.
Karen Berger medical writer and reviewer headshot
By | Updated on Dec. 30, 2024 Medically reviewed by Gerardo Sison, Pharm.D.
Pill representing Allegra vs Zyrtec drug comparison

Key takeaways

  • Allegra and Zyrtec are OTC antihistamines that treat allergy symptoms like sneezing and runny nose.

  • Zyrtec works faster and may last longer, but Allegra causes less drowsiness in most users.

  • Both medications are available in tablet and liquid forms, with Zyrtec also available as a chewable tablet.

  • Generic options for both medications are affordable and widely available without a prescription.

In this article:

If you are one of the 50 million Americans who live with allergies each year, you may have taken a walk down the allergy aisle at your local pharmacy. There are so many options that knowing which medication to choose can be difficult. Allegra (fexofenadine) and Zyrtec (cetirizine) are two medications that can help treat symptoms of allergies, such as runny nose, sneezing, and watery, itchy eyes. 

These brand-name allergy medicines are available in generic forms and can be purchased over the counter (OTC). They are classified in a class of medications called antihistamines, which work by blocking the effects of histamine. Histamine is a chemical the immune system makes in response to allergens like pollen and dust mites. Despite their similarities, Allegra and Zyrtec may have differences in effectiveness, cost, and other factors.

What are the main differences between Allegra and Zyrtec?

Allegra and Zyrtec are oral antihistamines that contain different active ingredients. Allegra contains fexofenadine, while Zyrtec contains cetirizine. 

As second-generation antihistamines, both medications are considered non-sedating. However, Allegra is believed to cause less drowsiness than Zyrtec. On the other hand, Zyrtec may work faster than Allegra, reaching maximum levels in the blood within an hour versus one to three hours with Allegra. In addition, the effects of Zyrtec may last longer than those of Allegra. 

Both medications can be used in adults and children. The typical adult dosage of Allegra is 180 mg daily as needed or 60 mg twice daily as needed. The typical adult dosage of Zyrtec is 5 to 10 mg daily as needed. Allegra and Zyrtec come in various forms, such as tablets, capsules, and oral liquids. However, Zyrtec is also available as a chewable tablet.

 

Main differences between Allegra and Zyrtec
Allegra Zyrtec
Drug class Antihistamine Antihistamine
Brand/generic status Brand and generic Brand and generic
What is the generic name? Fexofenadine Cetirizine
What form(s) does the drug come in? Tablet

Orally disintegrating tablet

Gelcap

Oral suspension

 Tablet

Orally disintegrating tablet

Chewable tablet

Gelcap

Oral syrup
What is the standard dosage? Adults: 180 mg daily as needed or 60 mg twice daily as needed

Children: varies by age

 Adults: 5 to 10 mg daily as needed

Children: varies by age
How long is the typical treatment? Short-term or long-term as needed Short-term or long-term as needed
Who typically uses the medication? Adults and children Adults and children

Conditions treated by Allegra and Zyrtec

Allegra and Zyrtec can both be used to treat perennial and seasonal allergic rhinitis. Perennial allergies can occur at any time of year and are related to dust and mold. Symptoms might include nasal congestion, runny nose, and itchy eyes. Both drugs are also indicated for the treatment of hives (urticaria) in children 6 months and older. 

Both drugs can often be used on an as-needed basis for symptoms of allergies. However, they don’t treat the root cause of allergies. Lifestyle changes such as avoiding allergens, keeping a clean living environment, and using air purifiers may help manage allergy triggers.

Is Allegra or Zyrtec more effective?

Both antihistamines are effective treatments for allergy symptoms compared to using nothing at all. However, studies suggest that Zyrtec may be more effective than Allegra. 

One study compared the effectiveness of fexofenadine and cetirizine in relieving seasonal allergic rhinitis symptoms. The results showed that cetirizine provided a 26% greater reduction in total symptom severity than fexofenadine 12 hours after taking the medication. 

Another study compared the effectiveness of these drugs in treating chronic idiopathic urticaria (CIU). It found that around 52% of patients taking cetirizine were symptom-free at the end of the treatment period, while only around 4% of those on fexofenadine achieved the same outcome.

Still, other studies suggest that Allegra and Zyrtec are similarly effective. One double-blind study looked at 495 patients with seasonal allergies and compared Allegra 180 mg daily to Zyrtec 10 mg daily for two weeks. Both drugs were found to be equally effective in treating allergy symptoms, and Allegra was found to cause less drowsiness than Zyrtec. 

Some people prefer one over the other, so it may take some trial and error to determine which drug is more effective for you. Consult a doctor or healthcare provider to help you choose the best option for your symptoms.

Coverage and cost comparison of Allegra vs. Zyrtec

Allegra and Zyrtec aren’t typically covered by insurance because they’re widely available over-the-counter medications. However, some government plans, such as Medicaid, may pay for Allegra or Zyrtec with a doctor’s prescription. 

A typical bottle of Allegra or Zyrtec could cost around $30 over the counter. However, you could get a better price by opting for generic versions of these medications. Retail prices generally depend on the pharmacy, the strength, and the quantity you purchase.

With a SingleCare discount card, you could save on the cash price of these medications. However, your healthcare provider will have to write a prescription for you to be able to take advantage of these savings. 

Allegra Zyrtec
Typically covered by insurance? No No
Typically covered by Medicare Part D? No No
Quantity 30 tablets 30 tablets
Typical Medicare copay Varies Varies
SingleCare cost $4 $12

Common side effects of Allegra vs. Zyrtec

Allegra and Zyrtec are well tolerated by most people. However, they may still come with side effects. In most cases, these side effects are mild and only last as long as you’re on the medication. 

The most common side effects of Allegra include:

  • Headache
  • Back pain
  • Dizziness
  • Upset stomach
  • Nausea
  • Upper respiratory tract infections

The most common side effects of Zyrtec include:

  • Drowsiness
  • Fatigue
  • Dry mouth
  • Sore throat
  • Dizziness

Other side effects may occur. Consult your allergist or other healthcare professional for a full list of potential side effects. 

Drug interactions of Allegra vs. Zyrtec

While Allegra and Zyrtec are effective for the quick relief of allergy symptoms, they may interact with other drugs. Certain medications and substances may alter the effectiveness of Allegra, while other medications may increase the side effects of Zyrtec. 

Antacids

Allegra should not be taken close to antacids that contain aluminum or magnesium, like Maalox. These drugs can reduce the amount of Allegra your body absorbs, making it less effective. Zyrtec does not have this interaction.

Alcohol and sedatives

Combining Zyrtec with alcohol or sedative drugs, such as painkillers, antidepressants, and sleep aids, can increase drowsiness from Zyrtec. Although Allegra is less likely to cause drowsiness than Zyrtec, it’s still recommended to use caution when taking Allegra with other substances that can cause sleepiness.

Other medications

Allegra can interact with antibiotics like Erythrocin (erythromycin) and antifungals like Nizoral (ketoconazole), which can increase the levels of Allegra in the body. However, this increase is not known to cause harmful side effects. 

Fruit juices

Drinking grapefruit, apple, or orange juice with Allegra may reduce the medication’s effectiveness by lowering the amount your body absorbs. To maximize its effectiveness, Allegra should be taken with water. Zyrtec does not interact with fruit juices.

Consult your healthcare provider for a full list of drug interactions, especially if you take other prescription medications, OTC medicines, or herbal supplements. 

Warnings of Allegra and Zyrtec

Both Allegra and Zyrtec can cause drowsiness, so avoid driving or using machinery until you know how they affect you. Allegra is generally safe but should be used with caution if you have kidney disease. A healthcare provider may need to adjust the dose to avoid side effects. 

Zyrtec may cause drowsiness more often than Allegra, so extra care is needed with activities that require full attention. While rare, Zyrtec can sometimes cause weight gain in breastfeeding infants if used by nursing mothers. If you have severe kidney problems, Zyrtec should also be avoided or used with caution due to an increased risk of side effects. Dosages may need to be changed if you have liver problems, as the medication can stay in the body longer. 

Consult a healthcare provider about other potential warnings and precautions before taking Allegra or Zyrtec. 

Frequently asked questions about Allegra vs. Zyrtec

What is Allegra?

Allegra is an OTC allergy medication that helps treat symptoms of hay fever and other allergic reactions, such as itching and skin rashes. It contains the active ingredient fexofenadine and is available in different forms, including tablets and gelcaps. 

What is Zyrtec?

Zyrtec is another OTC antihistamine used to treat allergy symptoms like an itchy nose, watery eyes, and sneezing. Its active ingredient is cetirizine. Zyrtec is available in various forms, such as chewable tablets and syrups, providing effective relief for both young children and adults.

Are Allegra and Zyrtec the same?

While both Allegra and Zyrtec are antihistamines, they contain different active ingredients. These medications have similar uses but have different side effects and may work differently for some. It’s important to consult a healthcare provider to determine the best choice for your needs.

Is Allegra or Zyrtec better?

The effectiveness of Allegra versus Zyrtec can vary depending on the person. Both medications can offer long-term allergy relief and are considered among the safest antihistamines available. However, studies suggest Zyrtec works faster than Allegra. Consult a healthcare provider to determine the best OTC antihistamine medication for your symptoms.

Can I use Allegra or Zyrtec while pregnant?

Using antihistamines during pregnancy should only be done with guidance from a healthcare provider. Both medications are generally considered safe for pregnant women, but individual health conditions and the severity of symptoms are important considerations. Always seek medical advice before starting any new medication during pregnancy.

Can I use Allegra or Zyrtec with alcohol?

It is generally recommended to avoid consuming alcohol while taking Allegra or Zyrtec. Mixing these medications with alcohol can increase the risk of experiencing severe side effects, such as drowsiness and dizziness. For safer use, consult a healthcare provider about the best way to manage your allergy symptoms without alcohol.

Can I take Zyrtec and Allegra together?

Combining Zyrtec and Allegra is not a good idea. Unless your doctor tells you otherwise, it is best to pick one appropriate allergy medication and take it as directed. Combining these medications does not typically offer additional benefits and may increase the risk of adverse effects. 

Which antihistamine is best?

That depends. Some people swear by Allegra, while others love Zyrtec. Other non-sedating antihistamines such as Claritin and Xyzal are also popular. It may take a bit of trial and error to find which antihistamine helps your symptoms the most while giving you the least side effects. Although these newer antihistamines may still cause drowsiness, they cause less drowsiness than first-generation antihistamines like Benadryl (diphenhydramine), which more easily cross the blood-brain barrier. 

Does Zyrtec raise blood pressure?

Zyrtec alone does not increase blood pressure. However, Zyrtec-D contains pseudoephedrine, which can increase blood pressure. Ask a pharmacist if you need help selecting an antihistamine medication that does not contain a decongestant.

Is it better to take Zyrtec at night or in the morning?

Depending on your symptoms and lifestyle, Zyrtec can be taken in the morning or at night. Some prefer taking it at night to avoid any drowsiness during the day. Consult a healthcare provider to determine the best time to take this medication.

What are the long-term effects of taking Zyrtec?

Long-term use of Zyrtec is generally considered safe for most people, as the medication can be used for perennial allergies. However, some people may experience side effects such as dry mouth, dizziness, and fatigue. It’s important to consult a healthcare provider for regular check-ups to monitor any potential long-term effects and ensure the medication continues to be effective for your symptoms.