Compare Zyrtec vs. Phenylephrine

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

Zyrtec
(Cetirizine)

Sudafed Pe
(Phenylephrine)

Treats allergy symptoms. Zyrtec (Cetirizine) is a once-daily allergy relief medication that won't make you feel too sleepy.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.
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Reviews & ratings
Button Group. All currently active
Button Group. All currently active
5.158456486042693Zyrtec
Reviews for Zyrtec (Cetirizine)
76%
of people say Zyrtec (Cetirizine) is worth it
46%
say it works well
7%
say it's a big hassle
Reviews for Sudafed Pe (Phenylephrine)
44%
32% vs. Zyrtec (Cetirizine)
23%
23% vs. Zyrtec (Cetirizine)
10%
3% vs. Zyrtec (Cetirizine)
Side effects
ZyrtecPhenylephrine

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

FDA side effect reports for Zyrtec »

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

FDA side effect reports for Phenylephrine »
How it works
ZyrtecPhenylephrine
Zyrtec (Cetirizine) is an antihistamine. It blocks histamine, a chemical that causes congestion, itching, and other allergic reactions. Antihistamines can also make you sleepy, but Zyrtec is a low-drowsiness version.Sudafed Pe (Phenylephrine) is a decongestant. It narrows blood vessels and reduces swelling in your nasal passages to make breathing easier.
Type of medication
ZyrtecPhenylephrine
Antihistamine
2nd generation
Prescription or OTC
DecongestantPrescription or OTC
Available as
ZyrtecPhenylephrine
  • Pill
  • Liquid capsule
  • Dissolving tablet
  • Liquid
  • Pill
  • Nasal spray
  • Eye drops
  • Suppository
Used for (click to learn more)
ZyrtecPhenylephrine
Risk factors for serious side effects
ZyrtecPhenylephrine
    • Age 65 or older
    • Taking with alcohol
    • Taking other medicines that make you less alert
    • Current kidney disease
    • Current liver disease
    Detailed Zyrtec (Cetirizine) risks & warnings »
    • 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 »
    Pregnancy category
    ZyrtecPhenylephrine
    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
    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
    Alcohol
    No specific alcohol-related info.No specific alcohol-related info.
    Food
    No specific food-related info.No specific food-related info.
    Kidneys and liver
    • People with kidney or liver disease may need to take a lower dose of Zyrtec (Cetirizine) to prevent overdose. Talk with your doctor to be sure you are using the correct dose.
    No specific kidneys and liver-related info.
    Sex
    No specific sex-related info.No specific sex-related info.
    Sleep
    • People age 65 and older have a higher risk of troublesome side effects from taking antihistamine medications like Zyrtec (Cetirizine). Watch out for changes in vision, severe dry mouth, trouble urinating, or constipation. Also, feelings of drowsiness may leave you "unsteady" on your feet. This can make you more likely to fall causing broken bones or other serious injuries. Talk with your doctor before using Zyrtec (Cetirizine) and stop using it if you have side effects.
    • Shouldn't use it before you want to sleep.
    Weight
    No specific weight-related info.No specific weight-related info.
    Upsides and benefits
    ZyrtecPhenylephrine
    • Zyrtec (Cetirizine) works as well as other antihistamines to treat sneezing and runny nose, but causes less sedation.
    • Works well to also treat hives and itchy skin.
    • Zyrtec (Cetirizine) is available over the counter without a prescription.
    • It comes as a tablet, liquid, and quick-dissolving tablet.
    • It can provide quick relief of allergy symptoms for both kids and adults.
    • It's okay to take with most other medications because it has few drug interactions.
    • Most people don't get any side effects from Zyrtec (Cetirizine).
    • 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.
    Downsides and risks
    ZyrtecPhenylephrine
    • Although it works fast, its effectiveness wears off for some people over time.
    • Zyrtec (Cetirizine) can be slightly more sedating than Allegra or Claritin.
    • Some people find that other more sedating antihistamines, like Benadryl, are more effective for them than Zyrtec (Cetirizine).
    • If you have daily allergy symptoms, a prescription nasal steroid spray might be better for you long-term.
    • 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.
    Tips from our pharmacists for people taking the medication
    ZyrtecPhenylephrine
    • Starts working in a few hours. Only take it once a day.
    • Can make you feel sleepy, so take it at bedtime if needed.
    • Avoid some of the side effects by drinking plenty of non-caffeinated liquids.
    • If you need to use it for more than a few weeks, talk with your doctor about trying a nasal steroid instead since it might work better for you long-term.
    • Using an antihistamine eye drop instead can also work better to treat itchy or watery eyes.
    • 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.
    Learn more
    More about ZyrtecSide effectsReviews & ratingsAlternativesFDA package insert
    More about PhenylephrineSide effectsReviews & ratingsAlternativesFDA package insert