Compare Clarinex vs. Zyrtec

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

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Treats allergy symptoms. Clarinex (Desloratadine) is a good option for once-daily allergy relief. It doesn't make you feel sleepy, but you need a prescription.Treats allergy symptoms. Zyrtec (Cetirizine) is a once-daily allergy relief medication that won't make you feel too sleepy.
How it works
Clarinex (Desloratadine) is an antihistamine. It blocks histamine, a chemical that causes congestion, itching, and other allergic reactions.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.
Type of medication
2nd generation
Prescription only
2nd generation
Prescription or OTC
Available as
  • Pill
  • Dissolving tablet
  • Liquid
  • Pill
  • Liquid capsule
  • Dissolving tablet
  • Liquid
Used for (click to learn more)
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Reviews & ratings
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Reviews for Zyrtec (Cetirizine)
24% vs. Clarinex (Desloratadine)
34% vs. Clarinex (Desloratadine)
+13% vs. Clarinex (Desloratadine)
Side effects
  • Fever 12%
  • Diarrhea 12%
  • Ear, nose, or throat infection 8%
  • Fatigue 4%
  • Middle ear inflammation 4%
  • Sore throat 3%
  • Nausea 3%
  • Loss of appetite 3%
  • Vomiting 3%
  • Runny nose 2%
More Clarinex side effects »

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

FDA side effect reports for Zyrtec »
Risk factors for serious side effects
Coming soon.
    • 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 »
    Pregnancy category
    No specific alcohol-related info.No specific alcohol-related info.
    No specific food-related info.No specific food-related info.
    Kidneys and liver
    No specific kidneys and liver-related info.
    • 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 sex-related info.No specific sex-related info.
    No specific sleep-related info.No specific sleep-related info.
    No specific weight-related info.No specific weight-related info.
    Upsides and benefits
    • Relieves allergy symptoms like sneezing, runny nose, congestion, hives, or itchy skin.
    • Preferred for older people since it causes little to no drowsiness compared to other antihistamines like Diphenhydramine (Benadryl).
    • Works faster than other non-drowsy antihistamines like Loratadine (Claritin).
    • Side effects are rare and usually mild.
    • Available as a liquid or fast-dissolving tablet for people who don't like swallowing pills.
    • 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).
    Downsides and risks
    • May not work as fast as the other antihistamines that make you sleepy (like Benadryl).
    • Not a good medication for pregnant women to take.
    • 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.
    Tips from our pharmacists for people taking the medication
    • Starts working in an hour.
    • Take it once a day when needed.
    • Works the best if used regularly during allergy season.
    • Can give you a headache or diarrhea, but it rarely causes drowsiness or dizziness.
    • 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.
    Learn more
    More about ClarinexSide effectsReviews & ratingsAlternativesFDA package insert
    More about ZyrtecSide effectsReviews & ratingsAlternativesFDA package insert