Non-drowsy antihistamines, also called second-generation antihistamines, were developed to treat allergies without the sedation associated with older medications like chlorphenamine. They selectively block H1 histamine receptors in the body while minimally crossing the blood-brain barrier, which is why they are far less likely to make you sleepy.
Non-Drowsy Options Available in the UK
Three main non-drowsy antihistamines are widely available in UK pharmacies:
Cetirizine
- Dose: 10mg once daily
- Available over the counter under various brand names (Piriteze, Benadryl Allergy) and as generics
- Very affordable — often under £2 for 30 tablets
- May cause mild drowsiness in a small percentage of users
Loratadine
- Dose: 10mg once daily
- Available OTC under brand names (Clarityn) and generics
- One of the least sedating options, though marginally less potent than cetirizine for some people
- Safe for use during breastfeeding (NHS recommendation)
Fexofenadine
- Dose: 120mg once daily for hay fever (OTC as Allevia); 180mg on prescription
- The least sedating of all three — clinical trials show no difference from placebo
- More expensive than cetirizine or loratadine when bought OTC
- Should not be taken with fruit juice (reduces absorption)
How to Choose the Right One
There is no single "best" antihistamine for everyone. The right choice depends on your priorities:
- Budget-conscious? Cetirizine or loratadine generics offer excellent value
- Need zero drowsiness? Fexofenadine is the safest bet
- Breastfeeding? Loratadine is the NHS-preferred option
- Tried one without success? Switching to a different antihistamine often helps — they work slightly differently despite being in the same class
Tips for Getting the Most from Your Antihistamine
- Take it at the same time every day for consistent coverage
- Start before the pollen season begins for best results
- Combine with a steroid nasal spray if tablets alone are not enough
- Keep a spare pack at work or in your bag during peak season
If over-the-counter options are not controlling your symptoms, your GP can prescribe higher-strength options or combination treatments.