cetirizine vs loratadine
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 loratadine. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Zyrtec
Claritin
Cetirizine (Zyrtec) is an antihistamine medicine. It helps relieve allergy symptoms.
Loratadine is an antihistamine medicine. It helps relieve allergy symptoms.
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 allergy symptoms. It can help with a runny nose, itchy and watery eyes, and sneezing. It also helps with itching of the nose or throat caused by hay fever or other upper respiratory allergies.
Cetirizine blocks histamine in your body. Histamine is a natural substance that causes allergy symptoms. By blocking it, cetirizine reduces these symptoms.
Loratadine blocks histamine in your body. Histamine is a natural substance that causes allergy symptoms. By blocking it, loratadine reduces these symptoms.
- • Headache
- • Fatigue
- • Headache
- • Fatigue
- • Drowsiness
- Fatigue 12,861
- Pain 12,124
- Rash 9,771
- Abdominal Discomfort 9,317
- Alopecia 9,237
- Fatigue 6,414
- Nausea 5,699
- Headache 5,201
- Dyspnoea 4,664
- Diarrhoea 4,663
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.
If you are pregnant or breastfeeding, talk to your doctor before taking loratadine. They can help you weigh the risks and benefits.
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How to Read This cetirizine vs loratadine Comparison
cetirizine is classified in the Second-Generation Antihistamine drug class, while loratadine 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 loratadine has 26,641. 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 loratadine.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.