Loratadine vs Cetirizine: side-by-side comparison
Loratadine and Cetirizine belong to the same class (Second-generation H1 antihistamine). They share therapeutic approach but differ in mechanism nuances, half-life, side-effect profile and available formulations. This comparison summarises what is common and where they diverge.
| Property | Loratadine | Cetirizine |
|---|---|---|
| Therapeutic class | Second-generation H1 antihistamine | Second-generation H1 antihistamine |
| CAS | 79794-75-5 | 83881-51-0 |
| ATC | R06AX13 | R06AE07 |
| Molecular weight | 382.88 g/mol | 388.89 g/mol |
| Brands with this active ingredient | 1 | 1 |
What they share
Both are in the Second-generation H1 antihistamine class, giving them a common pharmacological architecture and many shared safety and management points. Choice within the class comes down to mechanism nuances, half-life, side-effect profile and individual response.
Key differences
Differences within the Second-generation H1 antihistamine class are what matter in practice: half-life, route of administration, equivalent doses, specific interactions, predominant side-effect profile and accumulated clinical experience. This page frames them; the prescribing information gives quantitative detail.
Mechanisms compared
Loratadine: Loratadine selectively blocks peripheral H1 histamine receptors, antagonising the effects of histamine released during allergic reactions. Cetirizine: Cetirizine selectively blocks peripheral H1 histamine receptors, antagonising the effects of histamine released by mast cells during allergic responses.
Indications compared
Loratadine: Loratadine is approved in adults and children for the treatment of allergic rhinitis, including seasonal and perennial forms, and chronic idiopathic urticaria. Cetirizine: Cetirizine is approved in adults and children for the treatment of allergic rhinitis, including seasonal and perennial forms, allergic conjunctivitis and chronic idiopathic urticaria.
Safety profile
Loratadine: Loratadine is generally very well tolerated. Cetirizine: Cetirizine is generally well tolerated.
Frequently asked questions
Is Loratadine better than Cetirizine? ▾
Neither is universally better. Loratadine and Cetirizine share the Second-generation H1 antihistamine class but differ in half-life, mechanism nuances and side-effect profile. The choice depends on the patient and the prescriber.
Can Loratadine and Cetirizine be combined? ▾
Combining two ingredients from the same Second-generation H1 antihistamine class is uncommon and, in most cases, adds no benefit over one at an appropriate dose. The decision is always the prescriber's.
Do they have the same side-effect profile? ▾
Partly yes — they share many Second-generation H1 antihistamine class effects, with nuances by mechanism and dose. The prescribing information lists differences.
Products with Loratadine
Products with Cetirizine
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.