Which to choose?
Loratadine: mild allergic rhinitis, when sedation must be avoided. Cetirizine: urticaria, itching, cases needing more potency. A barely sedating alternative is bilastine (Ilaxten in the UK, Bilaxten in Spain).
Point-by-point comparison
LoratadineH1 antihistamine (second generation)
Brands: Clarityn
VS
CetirizineH1 antihistamine (second generation)
Brands: Zirtek · Piriteze · Zyrtec
| Loratadine | Cetirizine | |
|---|---|---|
| Mechanism | Selective peripheral H1 receptor antagonist. Minimal CNS penetration. | H1 antagonist, slightly more potent, with greater mast-cell affinity. |
| Indications | Allergic rhinitis, urticaria. | Allergic rhinitis, urticaria (more effective than loratadine). |
| Adult dose | 10 mg/day. | 10 mg/day. |
| Onset of effect | 1-3 h | 20-60 min |
| Duration of effect | 24 h | 24 h |
| Pregnancy | Compatible. | Compatible. |
| Breastfeeding | Compatible. | Compatible. |
| Paediatric use | From 2 years (syrup). | From 2 years. |
| Advantages | Less sedating than cetirizine. No driving restriction. | More effective in urticaria. Faster onset of action. |
| Disadvantages | Less effective than cetirizine in urticaria. | More sedating than loratadine (10-15% of patients). Take care driving on the first doses. |
Source: BNF, EAACI, Spanish SmPC (AEMPS)
For guidance only. This does not replace the pharmacist's judgement or medical advice. Check the official Summary of Product Characteristics before any clinical decision.
Frequently asked questions
Which is better, loratadine or cetirizine?
Loratadine: mild allergic rhinitis, when sedation must be avoided. Cetirizine: urticaria, itching, cases needing more potency. A barely sedating alternative is bilastine (Ilaxten in the UK, Bilaxten in Spain).
Can loratadine or cetirizine be taken in pregnancy?
Loratadine: Compatible. Cetirizine: Compatible. Always ask a doctor or pharmacist before taking a medicine in pregnancy.
And while breastfeeding?
Loratadine: Compatible. Cetirizine: Compatible.