Allegra vs Zyrtec: Is There any Difference?

Allegra and Zyrtec are drugs that are usually recommended for the treatment of allergic reactions. These medicines are available in prescription and over-the-counter forms. The first thing that needs to be established is that these two drugs are used for the treatment of basically the same kind of health conditions. However, the components of each medicine are different. For instance, the primary active ingredient in Zyrtec is Cetrizine and the active ingredient in Allegra, on the other hand, is Fexofenadine. Both medications are under a class of drugs known as antihistamines.

Antihistamines function by obstructing a substance known as histamine in the body. Histamine is believed to be the root cause of many allergic symptoms in human bodies. By obstructing this substance, symptoms of hay fever or seasonal allergies are prevented.

Common Symptoms Treated by Allegra and Zyrtec

There are some regular symptoms that can be treated with Allegra and Zyrtec. Both medications are very effective in the treatment of these symptoms and as a matter of fact, they both take the same duration to start working in the body. These allergy symptoms include itching of the nose and throat, runny nose, watery or itchy eyes, sneezing, or hives. It is important to note that hives is not a usual symptom of seasonal allergies. Therefore, if you experience this symptom, you should consult your healthcare provider to be sure that it is not a symptom of another health condition. Although both Allegra and Zyrtec are very effective in the treatment of allergy symptoms, some studies have discovered that Zyrtec has more beneficial effects that last longer that Allegra.

Forms of the Drug

Both medications are available in different forms of over-the-counter version. They are both available in oral tablets, oral dissolving tablets, and oral gel capsules. In addition to this, Allegra is available in oral liquid suspension. Zyrtec is available in oral liquid syrup and generic oral chewable tablets. Both medications can be used by patients from age 2 and above. However, not all the forms are recommended for everyone. For instance, children will be better off taking the liquid form than the tablet. Before you take this medication, it is important to read the patient information leaflet carefully. The details of use and age appropriateness for each form of the drugs are well detailed in the drug information provided by your pharmacist or physician.

It is important to point out that many over-the-counter medications for cold and allergy have the same active ingredients. Therefore, using any other drugs with either Allegra or Zyrtec to treat cold and allergy may lead to an overdose of active ingredients. It is therefore essential that you seek medical opinion before you combine either of these medications with another one. Remember to use Allegra or Zyrtec according to the prescription given in the patient information guide and use it about the same time every day. This is to ensure maximum effect of the drug and also make sure that you have enough of the medication in your body system to minimize the effects of the allergy symptoms as well as reduce the potentials of the side effects.

Side Effects of Allegra and Zyrtec

There are some common mild side effects that can be experienced while taking Allegra or Zyrtec. However, these adverse effects resolve on their own as the body gets accustomed to the medication. Most of the reactions experienced while taking these medications do not require the attention of a medical practitioner. However, it is important that you inform your doctor if you experience any side effect that doesn't go away or makes you feel consistently uncomfortable. You need to call for urgent medical attention if you experience any severe side effect while using the drugs. Side effects that both drugs have in common include diarrhea and vomiting. The side effects that are peculiar to Allegra include a headache, dizziness, menstrual cramps, cough, and pain in the legs, arms, or back. For Zyrtec, peculiar adverse effects include drowsiness, dry mouth, excessive tiredness, and stomach pain.

Severe side effects that can be experienced while taking Allegra include hoarseness, itching, hives, rash, swelling of the throat, lips, face, tongue, hands, eyes, ankles, lower legs, or feet. Both medications can also cause trouble swallowing or breathing. It is important to mention that the list of adverse effects mentioned here is not exhaustive. If you therefore experience any serious side effects while using either of the medication, call for urgent medical help.

Drug Interactions

You should inform your physician if you are taking any other medication before taking Allegra or Zyrtec. Taking other medicines with either of the drug can affect the way your medications work. Drug Interactions can maximize or minimize the effect of Allegra or Zyrtec, or other medications you are taking. In addition to this, it can also increase the possible side effects of the drugs. Zyrtec can interact with other medications like Theophylline. Allegra can interact with drugs like Rifampin, Erythromycin, Ketoconazole, and antacids. If you are using antacids such as Mylanta or Maalox, wait for some hours before or after using Allegra. Antacids contain magnesium and aluminium that have the potentials to prevent the body from absorbing a high percentage of the active ingredient in Allegra. By using the medications at different times, you can minimize the possible interaction.

It is important to mention that both Allegra and Zyrtec may not be recommended for patients with other health conditions such as kidney disease. You should therefore inform your doctor of your medical history before you start using any of the drugs.


Both Allegra and Zyrtec come in similar forms and are usually prescribed for the same symptoms but there are some distinct differences between these two. It is important that you don't consume fruit juices while taking Allegra because it affects its effectiveness. Zyrtec can also cause more drowsiness. You need to consult your doctor to be able to know which of the drugs is right for you.