Compare Allegra vs. Sudafed

Head-to-head comparisons of medication uses, side effects, ratings, and more.

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Treats allergy symptoms. Allegra (Fexofenadine) relieves allergy symptoms without making you feel drowsy.Clears your sinuses. Sudafed (Pseudoephedrine) relieves stuffy nose, but it could keep you up at night. Don't forget your photo ID or you won't be able to buy it in the drugstore.
How it works
Allegra (Fexofenadine) is an antihistamine. It blocks histamine, a chemical that causes congestion, itching, and other allergic reactions.Sudafed (Pseudoephedrine) is a decongestant. It narrows blood vessels and reduces swelling in your nasal passages to make breathing easier.
Type of medication
2nd generation
Prescription or OTC
DecongestantPrescription or OTC
Available as
  • Pill
  • Dissolving tablet
  • Liquid
  • Pill
  • Extended release
  • Liquid
Used for (click to learn more)
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Reviews & ratings
Button Group. All currently active
Button Group. All currently active
Reviews for Allegra (Fexofenadine)
of people say Allegra (Fexofenadine) is worth it
say it works well
say it's a big hassle
Reviews for Sudafed (Pseudoephedrine)
+5% vs. Allegra (Fexofenadine)
14% vs. Allegra (Fexofenadine)
6% vs. Allegra (Fexofenadine)
Side effects
  • Vomiting 3%
  • Headache 3%
  • Cough 3%
  • Back pain 2%
  • Ear, nose, or throat infection 2%
  • Diarrhea 1%
  • Fever 1%
  • Runny nose 1%
  • Dizziness 1%
  • Stomach discomfort 1%
More Allegra side effects »

We haven’t found good data for Sudafed side effects.

FDA side effect reports for Sudafed »
Risk factors for serious side effects
  • Taking with alcohol
  • Taking other medicines that make you less alert
  • History of phenylketonuria (PKU)
Detailed Allegra (Fexofenadine) risks & warnings »
  • History of high blood pressure
  • History of heart problems
  • Age 65 years or older
  • History of seizures
  • Women of childbearing age
Detailed Sudafed (Pseudoephedrine) risks & warnings »
Pregnancy category
CFDA pregnancy category (Weigh risks vs. benefits)

Research studies with animals found harmful effects on unborn babies. It hasn’t been properly studied in humans. The benefits might outweigh the risks even if you’re pregnant. Talk with your doctor.

See the FDA package insert
NFDA pregnancy category (Unknown)

The FDA hasn’t classified this medicine’s effects on unborn babies. Talk with your doctor about this medicine if you’re pregnant or planning on it.

See the FDA package insert
No specific alcohol-related info.No specific alcohol-related info.
No specific food-related info.No specific food-related info.
Kidneys and liver
  • The dose needs to be adjusted for people with kidney problems.
No specific kidneys and liver-related info.
No specific sex-related info.No specific sex-related info.
No specific sleep-related info.
  • It can affect the quality of your sleep, so you can't take it too close to going to bed.
No specific weight-related info.No specific weight-related info.
Upsides and benefits
  • Relieves allergy symptoms, like sneezing, runny nose, and itching.
  • Approved to be used in kids and adults age 6 months and older.
  • Won't make you feel drowsy like some antihistamine medicines.
  • Available over-the-counter without a prescription.
  • Comes in many forms, such as a tablet, liquid, or quick-dissolving tablet.
  • It's okay to take with most other medications since it has very few interactions.
  • One of the best over-the-counter options to clear stuffy nose and help you breathe better.
  • Clears nasal congestion better than other decongestants like phenylephrine.
  • Can be helpful in relieving congestion-related headaches and pressure in your ears.
  • Available in regular and extended release forms.
Downsides and risks
  • For some people, the effects Allegra (Fexofenadine) has on allergies will wear off over time.
  • May not work as well as the first-generation antihistamines, like diphenhydramine (Benadryl).
  • The dose needs to be adjusted for people with kidney problems.
  • Pseudoephedrine (a decongestant) can make your heart race or make you feel anxious and restless.
  • It can affect the quality of your sleep, so you can't take it too close to going to bed.
  • Can raise blood pressure so check with your doctor before using it if you have high blood pressure or other heart conditions.
  • Sudafed (Pseudoephedrine) isn't as effective after using it for more than 4 days straight.
  • Need to show a photo ID to buy it in the drugstore and there is a limit on how much you can buy each visit.
Tips from our pharmacists for people taking the medication
  • Starts working in 1 to 2 hours depending on what dosage form you're taking.
  • Works best when taken regularly, even before symptoms are expected to appear.
  • Can make you feel dizzy or sleepy, so you can take it at bedtime.
  • Follow age-specific dosing and don't take more than recommended.
  • If symptoms get worse or you need to use it for more than a few weeks, talk with your doctor.
  • Starts working in 30 minutes.
  • You need to show an ID to buy Sudafed (Pseudoephedrine) in the drugstore because it contains pseudoephedrine.
  • Follow age-specific dosing instructions on how much to take. Don't take more than recommended on the package.
  • Don't take Sudafed (Pseudoephedrine) too close to bedtime since it can keep you awake.
  • Can cause an irregular or fast heartbeat, and can raise your blood pressure.
  • Talk to your doctor if your symptoms don't get better in 1 week.
Learn more
More about AllegraSide effectsReviews & ratingsAlternativesFDA package insert
More about SudafedSide effectsReviews & ratingsAlternativesFDA package insert