Compare Zyrtec vs. Allegra D

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

Zyrtec
(Cetirizine)

Allegra D
(Pseudoephedrine / Fexofenadine)

Treats allergy symptoms. Zyrtec (Cetirizine) is a once-daily allergy relief medication that won't make you feel too sleepy.Treats allergy symptoms and congestion. Allegra D (Pseudoephedrine / Fexofenadine) is a combination allergy medicine that's useful if you have congestion and runny nose.
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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

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Side effects
ZyrtecAllegra D

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

FDA side effect reports for Zyrtec »
  • Back pain 2%
More Allegra D side effects »
How it works
ZyrtecAllegra D
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.Allegra D (Pseudoephedrine / Fexofenadine) is a combination medicine that relieves allergy symptoms. Fexofenadine (an antihistamine) prevents allergy symptoms like runny nose, sneezing, and itching. Pseudoephedrine (a decongestant) clears your sinuses.
Type of medication
ZyrtecAllegra D
Antihistamine
2nd generation
Prescription or OTC
DecongestantAntihistamine
2nd generation
Prescription or OTC
Available as
ZyrtecAllegra D
  • Pill
  • Liquid capsule
  • Dissolving tablet
  • Liquid
  • Extended release
Used for (click to learn more)
ZyrtecAllegra D
Risk factors for serious side effects
ZyrtecAllegra D
    • 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 »
    • Taking with alcohol
    • Taking other medicines that make you less alert
    • History of high blood pressure
    • History of heart problems
    • Age 65 or older
    • History of seizure
    • Women of childbearing age
    Detailed Allegra D (Pseudoephedrine / Fexofenadine) risks & warnings »
    Pregnancy category
    ZyrtecAllegra D
    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.
    • Talk to your doctor if you have high blood pressure or kidney problems before using it.
    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.
    • The antihistamine (fexofenadine) can cause dizziness, drowsiness, dry eyes/mouth, and constipation.
    • The decongestant (pseudoephedrine) can make your blood pressure higher and can make it harder to sleep.
    • Avoid taking it close to bedtime to prevent trouble sleeping.
    Weight
    No specific weight-related info.No specific weight-related info.
    Upsides and benefits
    ZyrtecAllegra D
    • 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).
    • Available without a prescription in the drugstore.
    • It has two medications that work in different ways to help relieve nasal symptoms.
    • The antihistamine (fexofenadine) is useful for relieving itchy eyes, runny nose, or constant sneezing.
    • The decongestant (pseudoephedrine) is very good at relieving congestion.
    Downsides and risks
    ZyrtecAllegra D
    • 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.
    • Has more side effects than Allegra since it has pseudoephedrine in it.
    • The antihistamine (fexofenadine) can cause dizziness, drowsiness, dry eyes/mouth, and constipation.
    • The decongestant (pseudoephedrine) can make your blood pressure higher and can make it harder to sleep.
    • You must show a photo ID to buy this from behind the pharmacy counter. There's a maximum limit on how much you can buy in the pharmacy at a time.
    Tips from our pharmacists for people taking the medication
    ZyrtecAllegra D
    • 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.
    • It works best if you have nasal congestion and a runny nose.
    • Take on an empty stomach, 1 hour before eating or 2 hours after eating.
    • Shouldn't be used in kids younger than 12 years old.
    • Avoid taking it close to bedtime to prevent trouble sleeping.
    • Can cause dizziness, headache, or a fast heartbeat.
    • Talk to your doctor if you have high blood pressure or kidney problems before using it.
    • If symptoms get worse or you need to use it for more than a few weeks, talk with your doctor.
    Learn more
    More about ZyrtecSide effectsReviews & ratingsAlternativesFDA package insert
    More about Allegra DSide effectsReviews & ratingsAlternativesFDA package insert