Cetirizine is a non-drowsy antihistamine which comes in the form of an oral tablet and is taken to relieve allergy symptoms. It is commonly recommended to treat hay fever (also known as seasonal allergic rhinitis).

Cetrizine is available as oral tablets and contains 10mg of the active ingredient cetirizine hydrochloride. It works by blocking histamine receptors to reverse the effects of histamine, a substance produced in response to an allergy, causing symptoms like sneezing, a runny nose, and watery eyes. It starts working within 60 minutes of taking it and can significantly reduce the severity of hay fever symptoms.

Cetirizine is the generic name for cetirizine hydrochloride, but it is also available under the following brand names:

• Allacan
• Benadryl Allergy
• Piriteze Allergy
• Zirtek Allergy

Important: Branded medications contain the same active ingredients, dosage, and work in the same way as their generic alternatives, but generic medications tend to be cheaper to buy. Though be aware that they may also contain different inactive ingredients. A healthcare professional should be able to advise the most suitable option for you.

Cetirizine, also known as cetirizine hydrochloride, is an antihistamine that blocks the action of histamine to relieve allergy symptoms. This means that if you are allergic to a substance, like pollen, your immune system produces a chemical called histamine, which triggers common allergy symptoms. By blocking the histamine receptors, cetirizine stops an allergic reaction from occurring, reducing your symptoms, and making you feel more comfortable.

Cetirizine is a popular choice of antihistamine for hayfever because it’s less likely to make you feel drowsy than older medications. So, it is more suitable if you are working or need to drive while taking it. However, you should assess how your body reacts before driving or operating machinery while taking cetirizine for hay fever.

How long does cetirizine take to work?

Cetirizine effects begin to work between 20 to 60 minutes after you take it and last for up to 24 hours.

How effective is cetirizine?

One study shows that cetirizine resulted in a 25% greater reduction in hay fever symptom severity after 12 hours compared to fexofenadine.

Further research shows that cetirizine is suitable for people with mild to moderate asthma. A 6-week placebo-controlled trial found that cetirizine 10mg daily improved hay fever symptoms without affecting lung function. At the recommended dosage, cetirizine improves the quality of life in people with hay fever.

The recommended cetirizine dose is one 10mg tablet once a day. You should swallow each tablet whole with a glass of water, with or without food. Most people start to notice an improvement in their symptoms within an hour.

When to take cetirizine

You can take cetirizine at any time of day, but you should take it at the same time every day.

What if I forget to take cetirizine?

If you forget to take a cetirizine tablet, you should take one as soon as you remember, then wait 24 hours to take the next one. Do not take a double dose to make up for a forgotten dose.

Can I take 20mg of cetirizine?

No, the usual dose is one 10mg cetirizine tablet once per day. If you feel that the current dose isn’t working for you, speak to your doctor for advice. They may recommend increasing your dose, but you must not do this without consulting them first.

Cetirizine is available to buy without a prescription from most UK pharmacies and online doctor or pharmacy services.

Can I buy cetirizine online?

Yes, you can request cetirizine online from Superdrug Online Doctor by:

1. Filling out a brief health and lifestyle questionnaire.
2. Ordering your preferred treatment and making payment.
3. One of our doctors will review your order and questionnaire answers.
4. If approved, your treatment will be posted to your address or made available for collection at your local Superdrug Pharmacy.
5. If your order is not approved, one of our doctors will contact you via your account with other treatment options.

Can I buy cetirizine over the counter?

Yes, cetirizine is available over the counter from most UK pharmacies. You do not need a prescription to buy cetirizine 10mg tablets in the UK for hay fever relief. It is also available under the brand names Benadryl, Piriteze, and Zirtek.

Can I get cetirizine on the NHS?

No, cetirizine, along with other mild to moderate hay fever medications like loratadine and fexofenadine, are no longer available on an NHS prescription. However, they can be bought in high street pharmacies and from online doctor services like Superdrug Online Doctor.

Common cetirizine side effects include:

• sleepiness
• dizziness
• headaches
• diarrhoea
• feeling sick (nausea)
• dry mouth
• fatigue

Uncommon side effects include:

• feeling agitated
• abnormal feelings of the skin (paresthesia)
• abnormal pain
• itchy skin rash
• extreme fatigue
• generally feeling unwell

Rare side effects include:

• depression
• hallucinations
• aggression
• confusion
• sleeplessness
• convulsions
• rapid heartbeat
• abnormal liver function tests
• hives
• swelling caused by water retention (oedema)
• weight gain

Like all medications, cetirizine can cause side effects, but not everyone will get them.

How long do cetirizine side effects last?

Most cetirizine side effects are mild and will go away on their own as your body gets used to the medication, usually within a few days to weeks. However, if they become severe or are not subsiding, contact your doctor or pharmacist for further advice.

What to do if you get cetirizine side effects

If you are concerned about any side effects you are experiencing, speak to your doctor or pharmacist for advice.

If you get any of the following serious side effects, stop taking cetirizine and call 999 or get someone to take you to A&E:

• swollen lips, mouth, throat, or tongue
• breathing or swallowing difficulties
• skin, tongue, or lips turn blue, grey, or pale
• confusion, drowsiness, or dizziness
• collapse
• a skin rash that is swollen, raised, itchy, blistered, or peeling

Most mild cetirizine side effects can be managed at home by:

• taking over-the-counter painkillers like paracetamol and ibuprofen to treat headaches
• getting plenty of rest if you are tired or drowsy or dizzy, and avoid driving or operating machinery until you feel better
• staying hydrated and drinking plenty of water if you are feeling sick
• eating smaller, more frequent, bland meals and avoiding spicy foods if you are feeling sick

If you feel drowsy or dizzy while taking cetirizine 10mg tablets, it may be helpful to take half a tablet twice a day rather than 1 tablet once a day.

Cetirizine may not be suitable for everyone. Do not take cetirizine if you:

• are allergic to cetirizine hydrochloride or any of the other ingredients listed in the medication
• have end-stage kidney disease

Talk to your doctor or pharmacist before taking cetirizine if you:

• are a patient with renal insufficiency
• have trouble passing urine
• have epilepsy or are at risk of seizures
• are scheduled to have an allergy test

Cetirizine and other medications

Before taking cetirizine, let your doctor or pharmacist know if you are currently taking or plan to take any prescribed, over-the-counter, or herbal medications.

Cetirizine in pregnancy and breastfeeding

Cetirizine tablets should not be taken during pregnancy and breastfeeding. If you have hay fever symptoms, speak to your doctor or pharmacist about a more suitable medication.

Food and drink interactions

Cetirizine absorption is not affected by food. However, it is recommended that you avoid alcohol while taking cetirizine hydrochloride tablets.

Cetirizine is not the only hay fever treatment available. There is a range of prescription-only and over-the-counter medications available to suit your requirements and give you effective symptom relief.

At Superdrug Online Doctor, we can offer the following cetirizine alternatives:

Prescription-only

Fexofenadine

Fexofenadine is an alternative non-drowsy antihistamine that works similarly to cetirizine by blocking the actions of histamine. It is available over the counter in 120mg tablets and on prescription at a higher strength of 180 mg. It is also available under the brand name Telfast.

Neoclarityn

Neoclarityn is an antihistamine that can effectively reduce allergy symptoms for up to 24 hours, with patients reporting significant improvements in symptoms compared to a placebo.

Neoclarityn is a brand name for the antihistamine, desloratidine, and works by blocking histamine receptors to provide effective relief from hay fever symptoms. It is available in oral tablet form.

Alongside antihistamine tablets, prescription-only nasal sprays are also available to help manage hay fever symptoms, including:

Avamys – A nasal spray that contains the active ingredient fluticasone furoate, a type of corticosteroid. It works by reducing inflammation in the nasal passages and is also available under the brand name, Flixonase.

Dymista – A nasal spray that contains an antihistamine called azelastine and a corticosteroid (fluticasone propionate). It works by relieving symptoms such as sneezing, a runny nose, and nasal congestion caused by allergies, including hay fever. Research shows it can reduce the severity of nasal symptoms by 50%.

Ryaltris – A combination nasal spray containing olopatadine (an antihistamine) and mometasone (a corticosteroid) that can treat eye and nasal hay fever symptoms.

Over-the-counter hay fever treatments

Like cetirizine, several hay fever medications are available to buy over the counter without a prescription from a doctor. These include:

Fexofenadine 120mg tablets – This lower dose of fexofenadine can be bought without a prescription in most UK pharmacies. Alternatively, you can request it from Superdrug Online Doctor. It works similarly to cetirizine by blocking the action of histamine and is a non-drowsy antihistamine.

Loratadine – Loratadine is a type of antihistamine that’s also available under the brand name Clarityn. It is available in 10mg tablets and is suitable for use during pregnancy. Loratidine is considered a safe and effective hay fever treatment that has been used by more than 10,000 people in controlled clinical trials.

Does cetirizine make you sleepy?

Although cetirizine is classed as a non-drowsy antihistamine, some people will experience drowsiness. Sleepiness is listed as a common cetirizine side effect in the patient information leaflet and may affect more than 1 in 10 people. If you experience sleepiness or drowsiness while taking cetirizine, you should avoid driving, operating machinery, or participating in other activities that require you to be alert until you feel better.

Can you take loratadine and cetirizine together?

No, it's generally not recommended that you take loratadine and cetirizine together, or any other antihistamine medications at the same time, without speaking to a doctor or pharmacist first.

Taking 2 antihistamines together may increase your risk of side effects.

Can I take cetirizine twice a day?

The usual daily dose for cetirizine is 10mg per day, that’s 1 tablet each day. However, if you are experiencing drowsiness, it is possible to take half a tablet twice a day, but you should speak to your doctor or pharmacist before doing this.

Is cetirizine the strongest antihistamine?

Cetirizine is considered one of the stronger second-generation, over-the-counter antihistamines available. However, more severe allergic reactions and hay fever responses may require more potent treatments that are only available with a prescription from a doctor.

How many hours does cetirizine stay in your system?

For most people, cetirizine is eliminated fully from the body within 24 to 48 hours. So, if you are experiencing side effects, they should go away after this time.

Does cetirizine cause weight gain?

Yes, weight gain is listed as a rare side effect of cetirizine. Some research published in 2011 found that H1 antihistamines, including cetirizine, can contribute to obesity and metabolic syndrome in adults. If you are worried about weight gain as a side effect, you should speak to your doctor or pharmacist before starting treatment.

Is cetirizine the same as Piriton?

No, cetirizine and Piriton are not the same. Piriton contains chlorphenamine, a first-generation antihistamine, while cetirizine is a second-generation antihistamine that is also sold under the brand names Benadryl, Piriteze, and Zirtek.