Generic name: fexofenadine [ FEX-oh-FEN-a-deen ]
Brand names: Allegra 12 Hour Allergy, Allegra 24 Hour Allergy, Allegra Allergy, Allegra OTC, Aller-Ease, ... show all 8 brands Allergy Relief (Fexofenadine HCl), Children's Allegra Allergy, Children's Allegra ODT
Dosage forms: oral suspension, oral tablet, oral disintegrating tablet
Drug class: Antihistamines

Medically reviewed by Carmen Pope, BPharm. Last updated on Jan 21, 2025.

What is fexofenadine?

Fexofenadine is an antihistamine that may be used to treat allergy symptoms (including hay fever) in adults and children.

Fexofenadine is also used to treat skin itching and hives caused by a condition called chronic idiopathic urticaria in adults and children who are at least 6 years old.

Fexofenadine works selectively on histamine-1 receptors that are located in our body, but not in our central nervous system - these are called peripheral histamine receptors. Because it acts on these receptors, fexofenadine is much less likely to cause drowsiness compared with some older antihistamines.

Histamine is a chemical that is released by mast cells in response to an allergen, and it is responsible for many allergy symptoms, such as watery eyes, a runny nose, sneezing, and itching. Fexofenadine binds to histamine receptors and prevents histamine from having an effect on those receptors, which reduces allergy symptoms.

There are many brands and forms of fexofenadine available.

Fexofenadine was FDA approved in 1996.

Warnings

Do not take fexofenadine with fruit juice (such as apple, orange, or grapefruit).

Before taking this medicine

You should not use fexofenadine if you are allergic to it.

Ask a doctor or pharmacist if fexofenadine is safe to use if you have:

• kidney disease.

Ask a doctor before using fexofenadine if you are pregnant or breastfeeding.

Older adults may be more sensitive to the effects of this medicine. If you are 65 or older, ask a doctor before taking fexofenadine.

This medicine may contain phenylalanine and could be harmful if you have phenylketonuria (PKU).

How should I take fexofenadine?

Take fexofenadine exactly as directed on the label, or as prescribed by your doctor.

Always follow directions on the medicine label about giving cough or cold medicine to a child.

• Ask a doctor before giving fexofenadine liquid to a child younger than 2 years old.

• The disintegrating (melting) tablets are not for use in a child younger than 6 years old.

• The 12-hour and 24-hour forms of fexofenadine are not for use in a child younger than 12 years old.

Take this medicine only with water.

Take the disintegrating tablet on an empty stomach.

Shake the oral suspension (liquid) before you measure a dose. Use the dosing cup provided, or use a medicine dose-measuring device (not a kitchen spoon).

Fexofenadine orally disintegrating tablets should only be removed from the package just before you are going to take them. Place the tablet on your tongue and allow it to dissolve, without chewing. Swallow several times as the tablet dissolves.

Call your doctor if your symptoms do not improve, or if they get worse.

Store fexofenadine in its original package at room temperature, away from moisture and heat. Do not allow liquid medicine to freeze.

What happens if I miss a dose?

Fexofenadine is used when needed. If you are on a dosing schedule, skip any missed dose. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms of fexofenadine may include a dry mouth, dizziness, or drowsiness.

What should I avoid while taking fexofenadine?

Do not take fexofenadine with fruit juice (such as apple, orange, or grapefruit). These juices can make it harder for your body to absorb fexofenadine.

Avoid taking an antacid within 2 hours before or after you take fexofenadine. Do not use fexofenadine at the same time as antacids that contain magnesium or aluminum.

Ask a doctor or pharmacist before using other cough or cold medicines that may contain similar ingredients.

Fexofenadine side effects

Get emergency medical help if you have signs of an allergic reaction to fexofenadine: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Fexofenadine may cause serious side effects. Stop using fexofenadine and call your doctor at once if you have:

• flu-like symptoms (fever, chills, unusual tiredness);

• new or worsening cough;

• pain; or

• signs of an ear infection--fever, ear pain or full feeling, trouble hearing, drainage from the ear, fussiness in a child.

Common side effects of fexofenadine may include:

• headache;

• back pain; or

• cold symptoms such as stuffy nose, sinus pain, sore throat.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Related/similar drugs

What other drugs will affect fexofenadine?

Using fexofenadine with other drugs that make you drowsy can worsen this effect. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.

Ask a doctor or pharmacist before using fexofenadine with any other medications, especially:

• ketoconazole; or

• erythromycin.

This list is not complete. Other drugs may affect fexofenadine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

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Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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