Compare Phenylephrine vs. Benadryl

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

Sudafed Pe
(phenylephrine)

Benadryl
(diphenhydramine)

Clears your sinuses. Sudafed Pe (Phenylephrine) is a good medication for relieving stuffy nose. It doesn't work as well as pseudoephedrine (Sudafed), but it has fewer side effects.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 Phenylephrine
Best available price for 1 (2ml of 2.5%) eye dropper of phenylephrine
Coupons for Benadryl
Best available price for 30 (25mg) capsules of benadryl
Reviews & ratings
Filter group. All currently selected
Filter group. All currently selected
4.18Phenylephrine
Reviews for Phenylephrine
44%
of people (All ages) say Phenylephrine is worth it
24%
say it works well
10%
say it's a big hassle
164 reviews
Have you used Sudafed Pe (phenylephrine)?
Worth itNot sureNot worth it
Reviews for Benadryl
86%
-42% worse vs. Phenylephrine
59%
-35% worse vs. Phenylephrine
8%
-2% worse vs. Phenylephrine
294 reviews
Have you used Benadryl (diphenhydramine)?
Worth itNot sureNot worth it
Side effects
PhenylephrineBenadryl

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

FDA side effect reports for Phenylephrine »

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

FDA side effect reports for Benadryl »
How it works
PhenylephrineBenadryl
Sudafed Pe (Phenylephrine) 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
PhenylephrineBenadryl
Prescription or OTCPrescription or OTC
Available as
PhenylephrineBenadryl
  • Pill
  • Nasal spray
  • Eye drops
  • Suppository
  • Pill
  • Oral solution
  • Cream, gel, or ointment
Used for
PhenylephrineBenadryl
Risk factors for serious side effects
PhenylephrineBenadryl
  • History of high blood pressure
  • Taking MAO inhibitors
  • History of heart problems
  • Age 65 years or older
  • Women of childbearing age
Detailed Sudafed Pe (phenylephrine) 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
PhenylephrineBenadryl
No alcohol related info.
  • Don't take it with alcohol or other drugs that make you sleepy.
Sleep
PhenylephrineBenadryl
No sleep related info.
  • 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
PhenylephrineBenadryl
  • Works to clear nasal congestion and helps you breathe better.
  • Helpful in relieving congestion-related headaches.
  • Has fewer side effects than other decongestants like pseudoephedrine.
  • It doesn't raise your blood pressure and heart rate as much, or cause as much trouble falling asleep.
  • Doesn't give you rebound congestion (worse symptoms when you stop taking it) like nasal spray decongestants do.
  • 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
PhenylephrineBenadryl
  • Phenylephrine doesn't last as long as other decongestants like pseudoephedrine (Sudafed).
  • You shouldn't use it if you have high blood pressure.
  • Can make your heart race or make you feel anxious and restless.
  • Shouldn't use it before you want to sleep.
  • Not as effective after using it for 4 days in a row.
  • 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
PhenylephrineBenadryl
  • Starts working in 30 minutes.
  • Phenylephrine can make you restless, so don't take it too close to bedtime.
  • It's in other cold and flu combination medicines. Read labels closely so you don't accidentally double up and take too much of it in a day.
  • Follow age-specific dosing instructions on how much to take.
  • Let your doctor know if your symptoms don't improve in a few days.
  • 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 PhenylephrineSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Sudafed Pe (phenylephrine)?
Worth itNot sureNot worth it
More about BenadrylSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Benadryl (diphenhydramine)?
Worth itNot sureNot worth it