What You Should Know About Allegra vs. Allegra-D

Allegra (fexofenadine) is an over-the-counter allergy medication used to treat seasonal allergy symptoms. In 2011, Allegra transitioned from prescription-only availability to over-the-counter purchase. In addition, it is now available in generic form.

Allegra-D is a combination of fexofenadine and pseudoephedrine. It can be used to treat seasonal allergies or relieve congestion (stuffy nose).

This article discusses the differences and similarities between Allegra and Allegra D, including its uses, dosing, side effects, and more.

young woman suffering spring allergy and blowing nose with a tissue in the nature
raquel arocena torres / Getty Images

Main Difference Between Allegra and Allegra D

The main differences between Allegra and Allegra-D allergy medications are the active ingredients.

Fexofenadine, an antihistamine, is the active ingredient in the brand-name medication Allegra. Many store brands and other companies are now able to offer generic fexofenadine.

Allegra-D is different in that it is a combination medication. It contains both fexofenadine and pseudoephedrine. Pseudoephedrine is a decongestant. Allegra-D fights both sneezing/runny nose and congestion. The "D" stands for decongestant, which will help relieve sinus congestion.

It is important to note that decongestants should not be taken long-term, so if you choose to take Allegra-D, do not take it for more than a few days before switching to a medication that does not contain a decongestant.

Is Allegra or Allegra-D More Effective?

There are no head-to-head trials to compare the effectiveness of Allegra and Allegra-D. Both can treat allergy symptoms like sneezing, itchy eyes, and itchy throat, but Allegra-D may provide some extra relief for nasal congestion. Ask your healthcare provider if you have any questions about which one you should choose for your symptoms.

Dosing Information

Allegra is available in different forms, including capsules, tablets, dissolve tabs, and liquid.

  • Allegra 24-Hour is a 180 milligram (mg) tablet or capsule taken once a day.
  • Allegra 12-Hour is a 60 mg tablet taken twice a day.
  • Children's Allegra Allergy 12-Hour liquid is available over the counter. Children 12 and older should take 10 mL every 12 hours. Children 2 to 11 should take 5 mL every 12 hours. Don't use it for children under 6.
  • Children's Allegra Allergy 12-Hour dissolve tabs are also available over the counter. Children 12 and over should take two tablets every 12 hours. Children 6 to 11 should take one tablet every 12 hours. Don't use it for children under 6.

Allegra-D is available in tablets for adults and children 12 years and older:

  • Allegra-D 24-Hour contains 180 mg of fexofenadine and 240 mg of pseudoephedrine and is taken once a day.
  • Allegra-D 12-Hour contains 60 mg of fexofenadine and 120 mg of pseudoephedrine and is taken twice a day.

Allegra and Allegra-D should not be taken at the same time as fruit juices. It should be taken on an empty stomach with a full glass of water. Taking it with fruit juice could make it less effective.

Safety and Side Effects

Side effects of Allegra may include:

  • Headache
  • Vomiting/nausea
  • Stomach pain
  • Drowsiness
  • Diarrhea
  • Pain in arms, back, or legs
  • Cough

Call your healthcare provider immediately if you experience any serious side effects after taking Allegra. These could include:

  • Hives
  • Rash/itching
  • Swelling
  • Difficulty breathing or swallowing

Allegra-D can cause side effects such as:

  • Headache
  • Nausea
  • Stomach pain
  • Back pain
  • Dry mouth
  • Throat irritation
  • Heartburn

Call your healthcare provider immediately if you experience serious symptoms after taking Allegra-D. Some of those symptoms may include:

  • Dizziness
  • Weakness
  • Fear/anxiety
  • Hallucinations
  • Seizures
  • Hives
  • Rash/itching
  • Shaking
  • Difficulty breathing/swallowing
  • Swelling
  • Hoarseness
  • Pounding, fast, or irregular heartbeat
  • Pain or difficulty with urination

How It Works

Allegra contains fexofenadine, an antihistamine that stops the effects of histamine in the body. Histamine is what causes allergy symptoms when a person is exposed to an allergen. Unlike some other antihistamines, Allegra does usually not cause drowsiness. Certain serious side effects should not be ignored. If you experience any of the following, contact your healthcare provider right away.

Allegra-D also contains pseudoephedrine, which temporarily relieves nasal congestion by narrowing blood vessels in the nasal passages.

Drug Interactions

Certain medications may cause interactions with Allegra and Allegra-D. Don't take antacids containing aluminum or magnesium within a few hours before or after taking Allegra or Allegra-D. If you're taking erythromycin or ketoconazole, check with your healthcare provider before taking Allegra or Allegra-D.

Also, don't take Allegra-D or other medications with pseudoephedrine if you've used a monoamine oxidase (MAO) inhibitor within the past two weeks.

Who Should Avoid Allegra or Allegra-D

Certain people should not take Allegra or Allegra-D. Do not take it if you are allergic to any of the ingredients in either Allegra or Allegra-D.

Talk to your healthcare provider before taking Allegra if you've ever had kidney disease or if you're pregnant or breastfeeding. Allegra is likely safe in pregnancy for humans, but some animal studies have suggested some risks.

For Allegra-D, there may be risks involved if you have certain conditions. Talk to your healthcare provider before taking Allegra-D if you have:

  • Glaucoma
  • High blood pressure
  • Difficulty urinating
  • Coronary artery disease
  • Angina
  • Diabetes
  • History of heart attacks
  • Hyperthyroidism
  • Enlarged prostate
  • Heart or kidney disease

Also, talk to your healthcare provider before taking Allegra-D if you are pregnant, plan to become pregnant, or are breastfeeding. Pseudoephedrine, which is found in Allegra-D, should be avoided in the first trimester of pregnancy.

Summary

Allegra (fexofenadine) is an antihistamine used to treat seasonal allergy symptoms. Allegra-D contains fexofenadine along with pseudoephedrine, a decongestant. Both medications treat allergy symptoms while Allegra-D may provide additional relief for nasal congestion.

Common side effects for both Allegra and Allegra-D include headache, nausea, and stomach pain. If you have certain medical conditions, like kidney disease, talk with your healthcare provider before using either medication.

4 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. MedlinePlus. Fexofenadine.

  2. MedlinePlus. Fexofenadine and pseudoephedrine.

  3. MedlinePlus. Pseudoephedrine.

  4. Servey J, Chang J. Over-the-counter medications in pregnancyAm Fam Physician. 2014;90(8):548-555.

Additional Reading
  • "Fexofenadine and Pseudoephedrine." Drugs and Supplements 1 Aug 10. PubMed Health. US National Library of Medicine.
  • "Allegra" Chattem 2011. Sanofi Pasteur.

By Kristina Herndon, RN
Kristina Herndon, BSN, RN, CPN, has been working in healthcare since 2002. She specializes in pediatrics and disease and infection prevention.