Cetirizine vs Famotidine: side-by-side comparison
Cetirizine (Second-generation H1 antihistamine) and Famotidine (H2-receptor antagonist) belong to different therapeutic classes and are rarely substitutes for each other. The comparison is useful when a single patient is weighing both options for adjacent or overlapping needs.
| Property | Cetirizine | Famotidine |
|---|---|---|
| Therapeutic class | Second-generation H1 antihistamine | H2-receptor antagonist |
| CAS | 83881-51-0 | 76824-35-6 |
| ATC | R06AE07 | A02BA03 |
| Molecular weight | 388.89 g/mol | 337.45 g/mol |
| Brands with this active ingredient | 1 | 1 |
What they share
Cetirizine and Famotidine share the common regulatory framework for prescription active ingredients, bioequivalence standards for generics, and pharmacist oversight. Beyond that, points in common are limited.
Key differences
Cetirizine acts by a different mechanism than Famotidine, with indications that barely overlap. Comparing the two is useful when a clinician has mentioned both in the same context or the patient wants to understand why one was prescribed instead of the other.
Mechanisms compared
Cetirizine: Cetirizine selectively blocks peripheral H1 histamine receptors, antagonising the effects of histamine released by mast cells during allergic responses. Famotidine: Famotidine reversibly and competitively blocks histamine H2 receptors on gastric parietal cells, reducing both basal and stimulated gastric acid secretion.
Indications compared
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. Famotidine: Famotidine is approved in adults and children for short-term treatment of active duodenal and gastric ulcer, maintenance therapy of duodenal ulcer, gastro-oesophageal reflux disease, Zollinger-Ellison syndrome and other…
Safety profile
Cetirizine: Cetirizine is generally well tolerated. Famotidine: Famotidine is generally well tolerated.
Frequently asked questions
Is Cetirizine better than Famotidine? ▾
Cetirizine and Famotidine are not "better or worse" — they treat different things. The sensible question is which fits your specific need.
Can Cetirizine and Famotidine be combined? ▾
Whether they can be combined depends on the indications and the interaction profile of each. If both are in a single prescription, the prescriber has weighed it; in self-medication they should never be combined.
Do they have the same side-effect profile? ▾
No — they belong to different classes and have distinct side-effect profiles. Each has its own prescribing information.
Products with Cetirizine
Products with Famotidine
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.