cetirizine vs fexofenadine
PlainMeds reviewed this comparison against our methodology in August 2026. It places FDA and CMS record fields side by side, without recommending either medication.
Side-by-side comparison of cetirizine and fexofenadine. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Zyrtec
Allegra
Cetirizine (Zyrtec) is an antihistamine medicine. It helps relieve allergy symptoms.
Fexofenadine (Allegra) is an antihistamine medicine. It helps reduce hives and relieve itching.
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.
This medicine treats hives and itching caused by hives. It will not stop hives or allergic skin reactions from happening. Talk to your doctor if you have questions about your condition.
Cetirizine blocks histamine in your body. Histamine is a natural substance that causes allergy symptoms. By blocking it, cetirizine reduces these symptoms.
Fexofenadine blocks histamine in your body. Histamine is a natural substance that causes allergy symptoms. By blocking histamine, fexofenadine reduces itching and hives.
- • Headache
- • Fatigue
- • Headache
- • Fatigue
- • Nausea
- Fatigue 12,861
- Pain 12,124
- Rash 9,771
- Abdominal Discomfort 9,317
- Alopecia 9,237
- Headache 878
- Fatigue 858
- Nausea 778
- Pruritus 765
- Extra Dose Administered 700
Ask a doctor before use if you have liver or kidney disease. Children under 2 years of age should ask a doctor before use.
No specific warnings noted.
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.
It is not known if fexofenadine will harm your unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is also not known if fexofenadine passes into breast milk, so talk to your doctor if you are breastfeeding.
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How to Read This cetirizine vs fexofenadine Comparison
cetirizine is classified in the Second-Generation Antihistamine drug class, while fexofenadine 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 available over the counter.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, cetirizine has 53,310 submissions while fexofenadine has 3,979. 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 represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for cetirizine or fexofenadine.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.