Difference Between Allegra and Zyrtec

Seasonal Allergies are common in humans who may lead to hay fever, stomach infections, and much other discomfort to the human body.


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People generally tend to take over-the-counter medicines for such infections. In this article, we have penned down some pros and cons taking into consideration the basic ingredients of Allegra and Zyrtec.

Allegra and Zyrtec are the most prominent medication to cure allergies containing active ingredients to block histamine chemicals in the human body and prevent the speedy spread of allergy in the body.

Though Zyrtec effects last longer than Allegra Allegra has its significant ingredient to prevent lethargic symptoms inpatient.  

Allegra vs Zyrtec

The difference between Allegra and Zyrtec is about the drowsiness effect where Zyrtec is more likely to make you feel drowsy after intake of its dosage and Allegra is less likely to give the effect of drowsiness on the human body as it contains an antihistamine with an active ingredient that reduces the chances of drowsiness.

Allegra vs Zyrtec

Multiple companies are selling second-generation antidote fexofenadine for allergies in kids and adults, Allegra is the name for one of those brands selling fexofenadine drugs

to cure allergies, and also with stomach problems, colds, anxiety, and more.

Containing low risk for sedation in comparison to other brands Allegra is the most preferred medication. 

Zyrtec is the brand name for Cetirizine which helps to treat natural chemical histamine in the body that causes seasonal allergies.

It helps to cure watery eyes, runny nose, and certain skin infections developed due to histamine in the body. Out of certain side-effects, Zyrtec may cause few effects on thinking patterns therefore it is always avoidable with alcohol.

Comparison Table

Parameters of ComparisonAllegraZyrtec
BrandsAllegra is the brand identity for the medical drug namely fexofenadineZyrtec is the brand identity for the antihistamines drug namely cetirizine.
EffectsA person will realize the effect after 2 hours of taking Allegra medicine.Zyrtec starts its impact within an hour of dosage by the person.
Side-Effects.Allegra is likely to cause drowsiness, dry mouth, and nausea.   In terms of side effects, Zyrtec is more likely to cause drowsiness, sedation, and headache.
CombinationAllegra intake with grapefruit juice will decrease the adoption of medicine by 30%.Zyrtec will have no such interactions or combinations with any Food product.
ResultsIn relieving the symptoms of allergic rhinitis and urticarial problems Allegra is less effective.Zyrtec is more effective in curing allergic rhinitis and urticarial problems than Allegra as per studies.

What is Allegra?

The term Allegra refers to a drug containing Fexofenadine antihistamine which was invented to cure seasonal allergies, hay fever, etc. in kids and adults.

Apart from seasonal allergies it also takes care of skin itching and hives caused by a condition called chronic idiopathic urticaria. This medicine is generally prescribed by the physician for children above 6 years.

Since being a drug made up of a certain chemical substance, Allegra may cause several adverse effects in some people which include headache, back pain, drowsiness, and other impacts as per the health conditions of a person,

therefore it must be taken as per physician’s advice. Chronic idiopathic urticaria which is also known as skin infection due to unavoidable eating can also be cured with the help of Allegra intake.

Once a doctor diagnoses the person with seasonal allergies, hay fever, and another disease he will also prescribe medicines to overcome the side-effects of Allegra to prevent runny or stuffy nose, sore throat, etc.

The receptors in our body which make us tear up, watery eyes, itchiness tends to harm our routine body systems are overcome through the 3 dosages of Allegra with or without a meal for consecutively three days.

What is Zyrtec?

The term Zyrtec refers to a drug containing Cetirizine a second-generation antihistamine that was invented to cure allergic rhinitis, dermatitis, skin allergies, and urticaria similar to Allegra.

It works by blocking a natural substance in a human body namely the Histamine that a human body produces during an allergic movement.

Histamine affects those allergic cells and makes you feel discomfort whereas Zyrtec helps to recover from that.

If one is taking Zyrtec in seasonal allergy over the counter to treat him without medical prescription, it should be ensured before treating that Zyrtec has some post–effects such as headache, sinus, stuffy nose, and more.

People suffering from high cough, sneeze, heaviness in body parts tend to often demand quick relief.

The dosage of Zyrtec is based upon the age, medical treatment, and allergic factors of kids and adults. It is manufactured as syrup as well as a tablet separately for children and adults.

This medicine in general is available in syrup or chewable tablets to be taken once a day with a meal for effective results.

All the instructions regard to dosage of Zyrtec are prescribed over its packet at the time of purchase. No mandatory prescription is required to purchase this.

Main Differences Between Allegra and Zyrtec

  1. Compatibility: Allegra is not found to be compatible with apple juice, grape juice, etc. these may impact the absorption process of Allegra in the body whereas Zyrtec is found compatible with almost every fruit juice and food item.
  2. Drug Interactions: Allegra has interactions capabilities with drugs namely erythromycin, rifampin, and antacids on the other hand Zyrtec has interaction capabilities with drugs such as theophylline as it increases the chances of side effects with such drugs.
  3. Forms in which drug is available: Allegra is mainly available in Tablets, Gelcap, Oral Suspension and in combination with pseudoephedrine in contrast Zyrtec is available over the counter in Tablets, Liquigel, Oral Suspension, chewable tablets.
  4. Typical Dosage for adults: As prescribed for Allegra 180 mg daily as required or 60 mg twice daily and for Zyrtec 5 to 10 mg daily as required or directed by the medical consultant but for kids, it’s not generally possible in over the counter medication.
  5. Pros n Cons of Medication: Though Allegra takes effect after 2 hours of intake of medicine it caused less drowsiness impact on the patient in comparison to Zyrtec which starts working within 1 hour of intake and lasts for almost 24 hours and leads huge impact of drowsiness.


  1. https://www.sciencedirect.com/science/article/abs/pii/S0091674900795546
  2. https://www.proquest.com/openview/3194e87c2d287b5555f6d81a1191449c/1?pq-origsite=gscholar&cbl=28636

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