Walk into any pharmacy during June and you'll find an entire shelf dedicated to antihistamines. But with so many options, it can feel overwhelming. Choosing the wrong one can mean drowsy afternoons, poor symptom control, or wasted money on a tablet that simply doesn't work well for you.
Here's a practical guide to the most common options.
How antihistamines work
Hay fever symptoms — the sneezing, itching, and runny nose — are triggered when pollen lands on the mucous membranes and causes your immune system to release a chemical called histamine. Antihistamines work by blocking the receptors that histamine binds to, preventing that reaction from taking hold.
The key distinction to understand is between first-generation and second-generation antihistamines.
First-generation: effective but sedating
First-generation antihistamines like chlorphenamine (Piriton) cross the blood-brain barrier, which is why they cause drowsiness. For most people with hay fever, these are not the best choice for daytime use — impaired concentration and slower reaction times are real side effects.
That said, they can be genuinely useful if your symptoms are disrupting your sleep. Taking a sedating antihistamine at night can tackle both the symptoms and the sleep problem in one go.
Never drive or operate heavy machinery after taking a first-generation antihistamine. The drowsiness can be significant even if you don't feel obviously tired.
Second-generation: the modern standard
Second-generation antihistamines are the better choice for most people. They're non-sedating (or minimally so) and typically last 24 hours, meaning one tablet a day is sufficient.
The three most widely available options are:
- Cetirizine — fast-acting and very effective, but a small number of people find it slightly sedating
- Loratadine — the least sedating of the three; a good first choice if you're sensitive to side effects
- Fexofenadine — available over the counter at higher doses, and consistently rated as the least likely to cause drowsiness
Pollen Level
High Pollen Day
On high pollen days, taking your antihistamine first thing in the morning — before you go outside — makes a significant difference to how well it controls your symptoms.
The single most important tip
Antihistamines work best preventatively, not reactively. If you wait until you're already sneezing with streaming eyes, the histamine response is already in full swing and the tablet is playing catch-up.
On days when Achoo is forecasting high pollen levels, take your antihistamine before you leave the house — ideally with breakfast. Over time, you'll notice a dramatic difference compared to waiting until symptoms arrive.
What about nasal sprays?
For moderate-to-severe hay fever, antihistamines alone often aren't enough. A steroid nasal spray (like fluticasone or beclometasone) works differently — it reduces inflammation in the nasal passages directly. The important thing to know is that these sprays take several days of consistent use to reach full effect, so you need to start them before your season begins, not during it.
Many GPs recommend using both: a daily antihistamine for general symptom control and a nasal spray used consistently throughout the season. Together, they cover most bases.
If you're unsure which approach is right for you, it's worth speaking to a pharmacist — they can recommend a routine based on your specific symptoms.