Compare Allegra vs. Benadryl

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

Allegra
(fexofenadine)

Benadryl
(diphenhydramine)

Treats allergy symptoms. Allegra (Fexofenadine) relieves allergy symptoms without making you feel drowsy.Treats allergy symptoms and helps you sleep. Benadryl (Diphenhydramine) is great for allergies, but curl up on the couch after taking it and get ready for a nap.
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Coupons for Allegra
Best available price for 30 (24 hour) tablets of fexofenadine
Coupons for Benadryl
Best available price for 30 (25mg) capsules of diphenhydramine
Reviews & ratings
Filter group. All currently selected
Filter group. All currently selected
5.38Allegra
Reviews for Allegra (fexofenadine)
79%
of people (All ages) say Allegra (fexofenadine) is worth it
63%
say it works well
0%
say it's a big hassle
Have you used Allegra (fexofenadine)?
Worth itNot sureNot worth it
Reviews for Benadryl (diphenhydramine)
86%
+7% better vs. Allegra (fexofenadine)
59%
-4% worse vs. Allegra (fexofenadine)
8%
-8% worse vs. Allegra (fexofenadine)
294 reviews
Have you used Benadryl (diphenhydramine)?
Worth itNot sureNot worth it
Side effects
AllegraBenadryl
  • Menstrual cramps 2%
  • Headache 3%
  • Back pain 2%
  • Cough 3%
  • Ear, nose, or throat infection 2%
  • Fever 1%
  • Middle ear inflammation 2%
  • Runny nose 1%
More Allegra side effects »

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

FDA side effect reports for Benadryl »
How it works
AllegraBenadryl
Allegra (Fexofenadine) is an antihistamine. It blocks histamine, a chemical that causes congestion, itching, and other allergic reactions.Benadryl (Diphenhydramine) is an antihistamine. It blocks histamine, a chemical that causes congestion, itching, and other allergic reactions. It also makes you sleepy.
Type of medication
AllegraBenadryl
Prescription or OTC
Prescription or OTC
Available as
AllegraBenadryl
  • Pill
  • Dissolving tablet
  • Liquid
  • Pill
  • Oral solution
  • Cream, gel, or ointment
Used for
AllegraBenadryl
Risk factors for serious side effects
AllegraBenadryl
  • Taking with alcohol
  • Taking other medicines that make you less alert
  • History of phenylketonuria (PKU)
Detailed Allegra (fexofenadine) risks & warnings »
  • Using other drugs with the same ingredients
  • Age 65 years or older
  • Taking with alcohol
  • Taking other medicines that make you less alert
  • Children age 6 years and younger
Detailed Benadryl (diphenhydramine) risks & warnings »
Pregnancy

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.

Research studies with animals haven’t found a risk to unborn babies, but it hasn’t been properly studied in humans.

Alcohol
AllegraBenadryl
No alcohol related info.
  • Don't take it with alcohol or other drugs that make you sleepy.
Food
AllegraBenadryl
  • Some forms of Allegra (Fexofenadine) contain aspartame (phenylalanine). People who have phenylketonuria (PKU) can't break down the amino acid phenylalanine. It builds up and causes serious medical problems. If you have PKU, check to see which products you can use.
No food related info.
Kidneys and liver
AllegraBenadryl
  • The dose needs to be adjusted for people with kidney problems.
No kidneys and liver related info.
Sleep
AllegraBenadryl
  • Won't make you feel drowsy like some antihistamine medicines.
  • Can make you feel dizzy or sleepy, so you can take it at bedtime.
  • Benadryl (Diphenhydramine) makes you more tired than Claritin, Allegra, or Zyrtec.
  • Benadryl (Diphenhydramine) makes you tired, so take it before you go to sleep.
Upsides and benefits
AllegraBenadryl
  • 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.
  • Benadryl (Diphenhydramine) is often better than other antihistamines at treating allergy symptoms and hives.
  • It can provide quick relief of allergy symptoms for both kids and adults.
  • It makes you sleepy, so it'll help if your allergies are bothering you at night.
  • The effects wear off in 4 to 6 hours, so side effects don't last that long.
  • It comes as a tablet, capsule, liquid, and quick dissolving tablet.
Downsides and risks
AllegraBenadryl
  • 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.
  • Benadryl (Diphenhydramine) makes you more tired than Claritin, Allegra, or Zyrtec.
  • You shouldn't drive after taking Benadryl (Diphenhydramine) until you know how it affects you.
  • Talk to a pediatrician before giving Benadryl (Diphenhydramine) to a child.
  • It can increase the risk of falls, so elderly people shouldn't use Benadryl (Diphenhydramine).
  • Don't use Benadryl (Diphenhydramine) if you are breastfeeding.
Tips from our pharmacists for people taking the medication
AllegraBenadryl
  • 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.
  • Take it as needed every 4 to 6 hours.
  • Benadryl (Diphenhydramine) can make you dehydrated, so avoid this side effect by drinking plenty of fluids.
  • Benadryl (Diphenhydramine) makes you tired, so take it before you go to sleep.
  • Don't take it with alcohol or other drugs that make you sleepy.
  • If you need to use it for more than a few weeks, talk with your doctor. A different medication might work better for you long-term.
  • If you only have itchy or watery eyes, try using just an antihistamine eye drop.
Learn more
More about AllegraSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Allegra (fexofenadine)?
Worth itNot sureNot worth it
More about BenadrylSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Benadryl (diphenhydramine)?
Worth itNot sureNot worth it