Piriton vs Cetirizine vs Loratadine: Which Antihistamine?

Piriton, cetirizine or loratadine? If you’re trying to choose an antihistamine for hay fever, hives, itching or an insect bite, the differences between them can be confusing.

All three can help relieve allergy symptoms, but they contain different active ingredients and differ in how likely they are to cause drowsiness and how often they are usually taken. Your age, symptoms and other medicines can also affect which option is appropriate.

So, which antihistamine may suit you best? Here’s how Piriton compares with cetirizine and loratadine, including their drowsiness, common uses and key differences.

How Do Antihistamines Work?

When you have an allergic reaction, your body releases a chemical called histamine. This can trigger symptoms such as sneezing, a runny or blocked nose, itchy or watery eyes, itching and hives.

Antihistamines work by blocking the effects of histamine, helping to relieve many of these allergy symptoms. They are commonly used for conditions such as hay fever, hives and other allergic reactions.

Piriton vs Cetirizine vs Loratadine: Key Differences

Piriton, cetirizine and loratadine are antihistamines used to relieve allergy symptoms, but they contain different active ingredients and have different properties.

Frequency and age suitability can vary by product and formulation. Always check the specific packaging and patient information leaflet for the correct dose and directions.

Drowsy vs Non-Drowsy Antihistamines: What Does It Mean?

“Drowsy” and “non-drowsy” describe how likely an antihistamine is to make you feel sleepy or less alert.

Piriton contains chlorphenamine, which can cause drowsiness and may affect concentration and reaction times. Cetirizine and loratadine are generally less likely to cause sleepiness, but some people can still feel tired or drowsy after taking them.

If you feel sleepy, dizzy or less alert after taking an antihistamine, do not drive, cycle or operate machinery. Always follow the product instructions and ask a pharmacist if you are unsure. 

Which Antihistamine May Suit Different Symptoms?

Different symptoms can call for different considerations. Here’s where antihistamines may fit into some common situations.

Hay Fever

Hay fever can cause sneezing, a runny or blocked nose and itchy or watery eyes. Antihistamines can help relieve many of these symptoms.

If you need to stay alert during the day for work or other daily activities, a less-sedating antihistamine may be preferable.

For more advice, read our guide to hay fever in Ireland.

Hives

Hives cause raised, itchy patches on the skin and can occur as part of an allergic reaction. Antihistamines can help relieve the itching associated with hives.

If hives are accompanied by swelling of the lips, mouth or throat, difficulty breathing or other signs of a serious allergic reaction, seek emergency medical help.

Insect Bites

Insect bites can cause local itching, redness and swelling. An antihistamine may help relieve itching when it is caused by an allergic reaction.

For more practical advice on managing bites and knowing when to seek help, see our guide to insect bites.

Seek urgent medical attention if you develop difficulty breathing or swelling of the lips, mouth or throat after an insect bite.

Night-Time Itching

If itching is particularly troublesome at night, speak to a pharmacist about which treatment may be appropriate. A sedating antihistamine should not be used simply as a way to help you sleep.

If itching is persistent, severe or regularly affecting your sleep, speak to a pharmacist or GP to discuss the possible cause and appropriate treatment. 

When Should You Speak to a Pharmacist First?

An antihistamine that is suitable for one person may not be right for someone else. It is particularly important to ask a pharmacist for advice if: 

• You are choosing an antihistamine for a child.

• You are pregnant or breastfeeding.

• You have an existing medical condition.

• You take prescription medicines or other treatments.

• You have experienced side effects from antihistamines before.

• You are unsure whether your symptoms are caused by an allergy.

• Your symptoms are persistent, severe or getting worse.

Age limits, doses and directions can vary between products and formulations, so check the specific product packaging and patient information leaflet rather than assuming the same instructions apply to every antihistamine.

For allergy-related products and further support, explore our allergy & hay fever medicines.