September 19, 2021

Allegra Side Effects

Allegra is a second generation antihistamine that is intended to treat the symptoms of allergies. Comprised of the chemical fexofenadine, this medication is used to get rid of symptoms like sneezing, hives or swelling in the nose. When someone has an allergic reaction, histamine is released from the body and attaches to other cells. Once there, it causes the symptoms of an allergy. The biggest difference between this second generation antihistamine and the first generation antihistamines is the lack of drowsiness. Second generation antihistamines are not readily absorbed by the brain so they cause less drowsiness and fatigue than former versions of antihistamines.

Approved by the FDA in 1995, Allegra is available in 20, 60 and 180 milligrams tablets. Patients who take this Allegra should not take antacids at the same time. Certain antacids contain aluminum which can lower the absorption level of Allegra. Fruit juices like apple or grapefruit juice can also limit the absorption rate of Allegra.

Allegra Side Effects

Individuals who are taking Allegra may have common side effects like cough, sleepiness, muscle aches or headaches. On occasion, they may feel unusually weak or nauseous. Patients who are allergic to Allegra may develop a fever or a cough. Serous allergic reactions to Allegra may have difficulty breathing, rash, itching and swelling.

Some of the common side effects of Allegra may include:

allegra side effects– Dizziness
– Headache
– Cough
– Diarrhea
– Nausea
– Abdominal cramps
– Back pain
– Sleepiness
– Drowsiness
– Earache
– Vomiting
– Trouble breathing
– Decreased mental alertness

Anyone who has severe side effects should immediately notify their doctor. In some cases, patients may feel drowsy or unusually sleepy. Until the patient knows how the drug will affect them, they should avoid activities like driving or operating heavy machinery. To report any side effects, patients should call the FDA at 1-800-FDA-1088. In Canada, patients can contact Health Canada at 1-866-234-2345.


The effects of Allegra on pregnant women have not been studied enough. To be on the safe side, patients who are pregnant or nursing should avoid using Allegra or talk to their doctor first. A qualified physician can decide if the benefits of using Allegra outweigh any of the associated risks.

Children should not use Allegra until they are at least older than six months of age. Any child under the age of 11 should still visit a doctor before taking Allegra. The effects on children are not well documented so it should never be taken without a doctor’s supervision. Children should never use more than the recommended dose because they often experience the side effects worse than adults do.

Patients with impaired renal function should be careful about taking Allegra. This medication is excreted from the body through the kidneys. If the kidney is impaired, too much Allegra may build up in the body and become toxic for the patient. Older patients and individuals with renal impairment should be especially cautious when using Allegra. If older patients experience any negative side effects, they should see their doctor or physician as soon as possible.

Warnings for Phenylketonurics

Patients who have phenylketonurics should be aware that Allegra contains 5.3 milligrams of phenylalanine in every 30 milligram dose. Although this may not be enough to cause a problem in every patient, it could cause serious side effects in a patient with phenylketonurics. To be on the safe side, avoid taking Allegra unless your doctor approves.


Allegra should only be taken according to the directions that come with the medication. Patients should be wary not to overdose on the medication. Before taking any additional medications, patients should check with their doctor to see if the new medicine could negatively interact with Allegra. If the patient experiences any negative side effects while taking Allegra, they should contact their doctor. Only a physician can decide a course of treatment or if using Allegra is right for you.