Side Effects of Allegra for Kids

Allegra (fexofenadine) is an over-the-counter antihistamine used to treat allergies in children and adults. It's non-drowsy, and its effects are long-lasting. Allegra is approved for children who have allergic rhinitis (hay fever) and chronic idiopathic urticaria (hives).

The side effects of Allegra are usually mild and can include nausea, coughing, and vomiting, and rarely, more severe reactions like difficulty breathing and throat swelling.

Boy sneezing in classroom
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Allegra Products for Children

There are two Allegra products formulated specifically for children under 12:

  • Children's Allegra Oral Suspension: This liquid form of Allegra provides allergy relief for 12 hours and is especially helpful for children who can't yet swallow pills.
  • Children's Allegra Meltable Tablets: Allegra's melt-in-your-mouth tablets are easy to use for kids who don't like liquid medicine or cannot swallow pills. These tablets also provide allergy relief for 12 hours.

Children over age 12 can take adult versions of Allegra.


  • For children between the ages of 2 and 11, the recommended dosage of Children's Allegra Oral Suspension is 30 milligrams (mg) in 5 Milliliters, (mL) every 12 hours.
  • For children aged 6 and older, the recommended dosage of Children's Allegra Meltable Tablets is one 30 mg tablet every 12 hours, and it should not be taken with fruit juice.
  • Children over age 12 can take an adult dose of 180 mg once a day or 60 mg every 12 hours.

Children who miss a dose of Allegra should take the missed dose as soon as possible (if needed for symptom relief), but not if it's almost time for the next dose. Don't take two doses at once, and stick to the dosing schedule as much as possible.

Side Effects

Some children who take Allegra may experience side effects. These side effects are usually mild, but sometimes serious reactions can occur. Depending on the frequency and type of side effect, medical attention may be needed.

Mild Side Effects

Common side effects include:

  • Nausea
  • Dizziness
  • Coughing
  • Muscle, back, or joint pain
  • Diarrhea
  • Vomiting

These mild side effects may lessen over time as the child's body adjusts to the medicine. Still, if the side effects are severe or too bothersome for your child, discontinue the medication and contact your child's healthcare provider.

Severe Side Effects

Although rare, children may be allergic to Allegra.

A severe allergic reaction called anaphylaxis causes:

  • Itching
  • Hives
  • Rashes
  • Swelling of body, particularly the face, tongue, and throat
  • Shortness of breath or difficulty breathing

If your child takes Allegra and experiences any of the severe side effects listed above, you should get medical help immediately.

Also, if your child regularly takes Allegra, stopping the medication suddenly may cause withdrawal effects such as pruritus (itching) and trouble sleeping.

Warnings and Interactions

Taking Allegra with certain substances can increase the risk of side effects. Before you give Allegra to your child, know that it can interact with substances like:

Erythromycin and Ketoconazole

Erythromycin is an antibiotic used to treat bacterial infections, and ketoconazole is an antifungal typically used to treat skin infections. Both erythromycin and ketoconazole increase the absorption of Allegra, which can increase the risk of side effects.

Antacids Containing Aluminum and Magnesium

Antacid medications are used to treat upset stomach, indigestion, gas, and heartburn. Some common antacids, such as Maalox and Mylanta, contain aluminum and magnesium, and they prevent the body from effectively absorbing Allegra.

Fruit/Fruit Juices

Eating fruit or drinking fruit juices, such as orange and apple juice, can decrease the absorption of Allegra and reduce its effectiveness. Therefore, your child should avoid fruit or fruit juices for one to two hours before and after taking Allegra.

Frequently Asked Questions

How fast does Allegra for kids work?

Allegra for kids will typically start to work one hour after taking the medication.

A Word From Verywell

Be sure to talk with your healthcare provider if your child continually experiences mild side effects of Allegra and seek medical help if they show any severe symptoms. If Allegra does not work for your child, there are alternative allergy medications you can try, such as Claritin, Clarinex, or Zyrtec. If your child is old enough, your healthcare provider may prescribe a steroid nasal spray such as Flonase, Nasonex, or Rhinocort Aqua.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Allegra Allergy. Children’s Allegra Liquid.

  2. Allegra Allergy. Children’s Allegra Meltable Tablets.

  3. MedlinePlus. Fexofenadine.

  4. Allergy & Asthma Physicians of Rhode Island. The pros and cons of common antihistamines.

  5. Allegra. Highlights of prescribing information.

  6. Allegra Allergy. FAQs.

By Vincent Iannelli, MD
 Vincent Iannelli, MD, is a board-certified pediatrician and fellow of the American Academy of Pediatrics. Dr. Iannelli has cared for children for more than 20 years.