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Overview: Fexofenadine is an antihistamine that is taken to help treat allergy symptoms, such as a runny nose, itchy or watery eyes, sneezing, or an itchy nose or throat. Common side effects may include vomiting, headache, diarrhea, dizziness, and drowsiness. If you have trouble swallowing tablets, fexofenadine comes in other forms, including tablets that dissolve in your mouth and a liquid. 

Uses

What is fexofenadine used for?

Fexofenadine is commonly taken to help treat allergy symptoms, such as a runny nose, itchy or watery eyes, sneezing, or an itchy nose or throat. 

Fexofenadine may also be used for other conditions as determined by your health care provider.

How does fexofenadine work (mechanism of action)?

Fexofenadine is an antihistamine. It helps to reduce allergy symptoms by blocking the effect of a substance in your body called histamine.

How is fexofenadine supplied (dosage forms)?

Brands and other names

  • Allegra Allergy
  • Allegra Hives
  • Children’s Allegra Allergy

Dosage forms and strengths

  • 30 mg/5 mL oral suspension
  • 30 mg, 60 mg, 180 mg oral tablets
  • 30 mg orally disintegrating tablets

How should I store fexofenadine?

Fexofenadine should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place. Protect from moisture.

Side Effects

What are the most common side effects of fexofenadine?

The most common side effects of fexofenadine are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Vomiting
  • Headache 
  • Infection in the nose or throat, sore throat, or common cold symptoms
  • Fever
  • Pain in the legs, arms, or back
  • Painful periods
  • Diarrhea or stomach discomfort
  • Drowsiness or dizziness

There may be other side effects of fexofenadine that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of fexofenadine?

While less common, the most serious side effects of fexofenadine are described below, along with what to do if they happen.

Severe Allergic Reactions. Fexofenadine may cause allergic reactions, which can be serious. Stop taking fexofenadine and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Warnings & Precautions

Who should not use fexofenadine?

Allergies to Ingredients. People who are allergic to any of the following should not take fexofenadine.

  • Fexofenadine
  • Allegra Allergy
  • Allegra Hives
  • Children’s Allegra Allergy
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific fexofenadine products they stock.

What should I know about fexofenadine before using it?

If fexofenadine was prescribed to you by a health care provider, use it as prescribed. If you are taking over-the-counter (OTC) fexofenadine, read and follow the instructions that come with the product.

Do not share fexofenadine that was prescribed for you by a health care provider with other people, even if they have the same condition as you. It may harm them.

Keep fexofenadine out of the reach of children.

If you are taking fexofenadine liquid, use an accurate measuring device to measure your dose. A household spoon is not an accurate measuring device and may cause you to take the wrong dose. Ask your pharmacist to recommend an appropriate measuring device.

Fexofenadine liquid needs to be shaken well before measuring a dose. This will help make sure the medicine is evenly mixed so you get the correct and safe amount each time. 

If you are taking fexofenadine orally disintegrating tablets, place the tablet on your tongue and allow it to dissolve before swallowing. Take the tablet right away after you remove it from the blister pack.

People who are 65 and older can be at greater risk of some side effects from fexofenadine. Talk to your health care provider about your risks if you are in this age group.

Some fexofenadine products may have phenylalanine, which can be dangerous for people with a condition called phenylketonuria (PKU). If you have PKU, your body cannot break down phenylalanine. Ask your pharmacist if you have any questions about the ingredients in the specific fexofenadine product you have.

What should I tell my health care provider before using fexofenadine?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if fexofenadine is right for you.

In particular, make sure that you discuss any of the following.

Kidney Problems. Tell your health care provider if you have kidney problems. You may need a different dose of fexofenadine or a different medicine to relieve your allergy symptoms.

Other Medicines and Supplements. Fexofenadine may interact with other medicines and supplements. Before taking fexofenadine, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how fexofenadine could affect pregnancy or harm an unborn baby. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. It is not known if fexofenadine passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. 

Interactions

Does fexofenadine interact with foods or drinks?

Do not take fexofenadine with fruit juices. Fruit juice can reduce the amount of fexofenadine that your body absorbs and make the medicine not work as well. 

Fexofenadine orally disintegrating tablets should be taken on an empty stomach. 

It is unknown if drinking alcohol will affect fexofenadine. The risk of drowsiness or dizziness may be increased if you drink alcohol while taking fexofenadine.

Does fexofenadine interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are taking an antacid with aluminum or magnesium in it before taking fexofenadine.

This may not be a complete list of medicines that can interact with fexofenadine. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much fexofenadine?

If you or someone else has taken too much fexofenadine, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of fexofenadine?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.