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cetirizine vs desloratadine

Side-by-side comparison of cetirizine and desloratadine Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.

Drug Class
cetirizine Second-Generation Antihistamine
desloratadine Second-Generation Antihistamine
Type
cetirizine Over-the-Counter
desloratadine Prescription
Summary
cetirizine

Cetirizine (Zyrtec) is an antihistamine medicine. It helps relieve allergy symptoms.

desloratadine

Desloratadine is an antihistamine medicine. It helps relieve allergy symptoms.

What It Treats
cetirizine

This medicine treats allergy symptoms. It can help with a runny nose, sneezing, and itchy, watery eyes. It also helps with itching of the nose or throat caused by hay fever or other upper respiratory allergies.

desloratadine

This medicine treats allergy symptoms. It can help with seasonal allergies like hay fever. It also treats year-round allergies and chronic hives by reducing itching and the number and size of hives.

How It Works
cetirizine

Cetirizine blocks histamine in your body. Histamine is a natural substance that causes allergy symptoms. By blocking it, cetirizine reduces these symptoms.

desloratadine

Desloratadine blocks histamine in your body. Histamine is a substance that causes allergy symptoms. By blocking histamine, this medicine reduces those symptoms.

Common Side Effects
cetirizine
  • Headache
  • Fatigue
desloratadine
  • Sore throat
  • Dry mouth
  • Muscle pain
  • Tiredness
  • Sleepiness
FAERS Reports
cetirizine
  • The medicine did not work 12,977
  • Tiredness 12,862
  • Pain 12,124
  • Skin rash 9,771
  • Using the medicine for a condition it is not approved for 9,340
desloratadine
  • Medicine not working 605
  • Tiredness 602
  • Feeling sick to your stomach 583
  • Difficulty breathing 532
  • Head pain 465
Serious Warnings
cetirizine

Ask a doctor before use if you have liver or kidney disease. Children under 2 years of age should ask a doctor before use.

desloratadine

Stop taking this medicine and get medical help right away if you have an allergic reaction. Signs of a reaction include rash, itching, hives, swelling, trouble breathing, or anaphylaxis.

Pregnancy
cetirizine

Ask a doctor if you are pregnant or breastfeeding before taking this medicine. It is not known if cetirizine will harm your unborn baby or pass into breast milk.

desloratadine

Not enough studies have been done to know if desloratadine is safe during pregnancy. Talk to your doctor if you are pregnant or plan to become pregnant. It is not known if desloratadine passes into breast milk.

Also Compare — Nearby Drugs

How to Read This cetirizine vs desloratadine Comparison

cetirizine is classified in the Second-Generation Antihistamine drug class, while desloratadine sits within the Second-Generation Antihistamine class. Because both drugs share the same classification, they are often considered interchangeable in theory — but clinical outcomes rarely track that cleanly. Both drugs are split between OTC and prescription status, which affects access and supervision.

Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, cetirizine has 57,074 submissions while desloratadine has 2,787. Those figures reflect cumulative reporting volume — not per-patient risk — so older, widely dispensed drugs typically look worse on count alone. No direct interaction between these two drugs is listed in our FDA-derived dataset, though co-prescription still warrants pharmacist review. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between cetirizine and desloratadine — always consult your physician or pharmacist first.

Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.