Sudafed vs. Benadryl

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

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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.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.
How it works
Sudafed (Pseudoephedrine) is a decongestant. It narrows blood vessels and reduces swelling in your nasal passages to make breathing easier.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
DecongestantPrescription or OTC
1st generation
Prescription or OTC
Available as
  • Pill
  • Extended release
  • Liquid
  • Pill
  • Oral solution
  • Cream, gel, or ointment
Used for (click to learn more)
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Reviews & ratings
Button Group. All currently active
Button Group. All currently active
Reviews for Sudafed (Pseudoephedrine)
of people say Sudafed (Pseudoephedrine) is worth it
say it works well
say it's a big hassle
Reviews for Benadryl (Diphenhydramine)
+3% vs. Sudafed (Pseudoephedrine)
+12% vs. Sudafed (Pseudoephedrine)
-2% vs. Sudafed (Pseudoephedrine)
Side effects

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

FDA side effect reports for Sudafed »

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

FDA side effect reports for Benadryl »
Risk factors for serious side effects
  • 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 »
  • 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
  • Enlarged prostate
  • History of bladder problems
  • Glaucoma
  • Nursing mothers
Detailed Benadryl (Diphenhydramine) risks & warnings »
Pregnancy category
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
BFDA pregnancy category (Probably safe)

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

See the FDA package insert
No specific alcohol-related info.
  • Don't take it with alcohol or other drugs that make you sleepy.
No specific food-related info.No specific food-related info.
Kidneys and liver
No specific kidneys and liver-related info.No specific kidneys and liver-related info.
No specific sex-related info.No specific sex-related info.
  • It can affect the quality of your sleep, so you can't take it too close to going to bed.
  • Benadryl (Diphenhydramine) makes you tired, so take it before you go to sleep.
No specific weight-related info.No specific weight-related info.
Upsides and benefits
  • 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.
  • 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
  • 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.
  • 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
  • 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.
  • 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 SudafedSide effectsReviews & ratingsAlternativesFDA package insert
More about BenadrylSide effectsReviews & ratingsAlternativesFDA package insert