Cetirizine

About cetirizine

Cetirizine is an antihistamine medicine that relieves the symptoms of allergies. It’s used to treat hay fever, allergic conjunctivitis (red, itchy eye), eczema and hives. It’s also used for reactions to insect bites and stings and for some food allergies.

Cetirizine is known as a non-drowsy antihistamine. It's much less likely to make you feel sleepy than some other antihistamines.

Cetirizine is available on prescription. You can also buy it from pharmacies and supermarkets.

It comes as tablets, capsules and as a liquid that you swallow.

Key facts

It's usual to take cetirizine once a day. Children sometimes take it twice a day.
Cetirizine is classed as a non-drowsy antihistamine, but some people still find it makes them feel quite sleepy.
Common side effects include headache, dry mouth, feeling sick, dizziness, tummy pain and diarrhoea.
It’s best not to drink alcohol while you’re taking cetirizine as it can make you feel sleepy.
Cetirizine is also called by the brand names Benadryl Allergy, Piriteze and Zirtek.

Who can and can't take cetirizine

Cetirizine tablets and liquid that you buy from pharmacies and supermarkets can be taken by adults and children aged 6 and older.

Children over the age of 2 can also take liquid cetirizine for hay fever and skin allergies.

Cetirizine can also be taken under medical supervision by children aged 1 year and older.

Cetirizine isn't suitable for some people. Tell your doctor or pharmacist if you:

have had an allergic reaction to cetirizine or any other medicines in the past
have an allergy to peanuts or soya
have an allergy to the food additives, E218 or E216
have an intolerance to, or cannot absorb, some sugars such as lactose or sorbitol
have liver or kidney failure
have epilepsy or another health problem that puts you at risk of fits
have an illness that means you're more likely to retain pee
are booked to have an allergy test - taking cetirizine may affect the results, so you might need to stop taking it a few days before the test

How and when to take it

If you or your child have been prescribed cetirizine, follow your doctor's instructions about how and when to take it. If you've bought cetirizine from a pharmacy or shop, follow the instructions that come with the packet.

How much should I take?

Cetirizine comes as tablets and capsules (10mg) and as a liquid medicine (labelled either 5mg/ml or 1mg/1ml).

The usual dose in adults is 10mg once daily.

Doses are usually lower for people with kidney problems.

For children, your doctor will use your child's weight or age to work out the right dose. If you've bought cetirizine for a child, follow the instructions on the packet.

Depending on their age, children may take cetirizine twice a day. In this case, try to space the doses 10 to 12 hours apart.

How to take it

You can take cetirizine with or without food.

Always take cetirizine tablets or capsules with a drink of water, milk or juice. Swallow them whole. Do not chew them.

Cetirizine liquid may be easier for children to take than tablets or capsules. The liquid medicine will come with a plastic syringe or spoon to help you measure out the right dose. If you don't have a syringe or spoon, ask your pharmacist for one. Do not use a kitchen teaspoon as it will not give the right amount.

When to take it

You may only need to take cetirizine on a day you have symptoms, such as if you’ve been exposed to a trigger like animal hair. Or you may need to take it regularly to prevent symptoms, such as to stop hay fever during spring and summer.

What if I forget to take it?

Take your forgotten dose as soon as you remember, unless it is nearly time for your next dose. Do not take a double dose to make up for a forgotten dose.

If you forget to give a dose to a child who is taking cetirizine twice a day, you can give the dose if it's within 4 hours of when they should have had it. If you remember more than 4 hours after, do not give the missed dose. Instead, wait until the next dose and carry on as normal.

If you forget doses often, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.

What if I take too much?

Cetirizine is generally very safe. Taking too much is unlikely to harm you or your child.

If you take an extra dose by mistake, you might get some of the common side effects. If this happens or you’re concerned, contact your doctor.

Side effects

Like all medicines, cetirizine can cause side effects although not everyone gets them.

Common side effects

Common side effects of cetirizine happen in more than 1 in 100 people. Talk to your doctor or pharmacist if these side effects bother you or don’t go away:

feeling sleepy and tired
headache
dry mouth
feeling sick or dizzy
tummy pain
diarrhoea
sore throat
cold-like symptoms of the nose
itch or rash
tingling in the hands and feet
feeling agitated

Children are more likely to get diarrhoea or cold-like symptoms of the nose than adults.

Serious side effects

It's rare to have a serious side effect with cetirizine.

Tell your doctor straight away if you have:

bruising or bleeding that's more than normal

Serious allergic reaction

In rare cases, it’s possible to have a serious allergic reaction to cetirizine.

A serious allergic reaction is an emergency. Contact a doctor straight away if you think you or someone around you is having a serious allergic reaction.

The warning signs of a serious allergic reaction are:

getting a skin rash that may include itchy, red, swollen, blistered or peeling skin
wheezing
tightness in the chest or throat
having trouble breathing or talking
swelling of the mouth, face, lips, tongue, or throat

These are not all the side effects of cetirizine. For a full list see the leaflet inside your medicines packet.

You can report any suspected side effect to the UK safety scheme.

How to cope with side effects

What to do about:

feeling sleepy - try a different non-drowsy antihistamine. If this doesn't help, talk to your doctor.
feeling sick - stick to simple meals and don’t eat rich or spicy food
headache - take an everyday painkiller like paracetamol or ibuprofen
dry mouth - chew sugar-free gum or suck sugar-free sweets
diarrhoea - drink plenty of water in small, frequent sips. It may also help to take oral rehydration solutions. You can buy these from a pharmacy or supermarket to prevent dehydration. Don’t take any other medicines to treat diarrhoea without speaking to a pharmacist or doctor.

Cautions with other medicines

Some medicines and cetirizine interfere with each other and increase the chances of you having side effects. Check with your pharmacist or doctor if you're taking:

midodrine, a medicine used to treat low blood pressure
ritonavir, a medicine used to treat HIV infection
any medicine that makes you drowsy, gives you a dry mouth, or makes it difficult for you to pee. Taking cetirizine might make these side effects worse.

Mixing cetirizine with herbal remedies and supplements

There might be a problem taking some herbal remedies and supplements alongside cetirizine - especially ones that cause sleepiness, a dry mouth or make it difficult to pee.

Ask your pharmacist for advice.

Tell your doctor or pharmacist if you're taking any other medicines, including herbal remedies, vitamins or supplements.

Pregnancy and breastfeeding

You can take cetirizine while you're pregnant. However a similar antihistamine called loratadine is normally used first because there's more information to say that it's safe.

Cetirizine isn't thought to be harmful during pregnancy, but as very few pregnant women have been studied, it is not possible to be certain.

Talk to your doctor about the benefits and possible harms of taking cetirizine. It will also depend on how many weeks pregnant you are and the reason you need to take cetirizine.

Cetirizine and breastfeeding

It's usually safe to take cetrizine if you're breastfeeding as only small amounts get into breast milk.

However, speak to your doctor before taking cetirizine if your baby was premature, had a low birth weight or has other health problems.

For safety, tell your pharmacist or doctor if you're trying to get pregnant, are already pregnant or if you're breastfeeding.

Common questions

How does cetirizine work?

Cetirizine is a medicine called an antihistamine.

When you come into contact with something you're allergic to, such as pollen, animal hair or fur, house dust or insect bites and stings, your body produces a chemical called histamine.

Usually histamine is a useful substance but in an allergic reaction it causes unpleasant symptoms including itchy, watery eyes, running or blocked nose, sneezing and skin rashes.

Cetirizine blocks the effects of histamine and reduces these symptoms.

When will I feel better?

You should start to feel better within an hour.

How long should I take cetirizine for?

It depends on why you’re taking cetirizine.

You may only need to take it for a short time or as a one-off dose. For example, if you have a reaction to an insect bite, you may only need to take cetirizine for a day or 2.

You may need to take cetirizine for longer if you're taking it to prevent symptoms - for example, to stop hay fever when the pollen count is high.

Talk to your doctor or pharmacist if you’re unsure how long you need to take cetirizine for.

Is it safe to take cetirizine for a long time?

Cetirizine is unlikely to do you any harm if you take it for a long time. However, it’s best to take cetirizine only for as long as you need to.

Can I drink alcohol with it?

It’s best not to drink alcohol while you’re taking cetirizine as it can make you feel sleepy.

Is there any food or drink I need to avoid?

You can eat and drink normally while taking cetirizine.

Can I drive or ride a bike with it?

Cetirizine is classed as a non-drowsy antihistamine but it’s still possible to feel sleepy after taking it.

If this happens to you, don't drive a car or ride a bike until you feel better.

What's the difference between cetirizine and other antihistamines?

Cetirizine is known as a non-drowsy antihistamine. That’s because it's less likely to make you feel sleepy than other, so-called sedating antihistamines such as Piriton (chlorphenamine).

Most people prefer to take a non-drowsy antihistamine instead of a sedating one. An exception is when you want the medicine to make you sleepy, for example if you have itchy skin that’s keeping you awake.

What's the difference between cetirizine and other non-drowsy antihistamines?

Other non-drowsy antihistamines like loratadine, desloratadine, fexofenadine, levocetirizine seem to work just as well as cetirizine.

However, cetirizine seems to be more likely to make you feel sleepy than loratadine, desloratadine or fexofenadine.

Can I take it with painkillers?

Yes, you can take cetirizine together with paracetamol or ibuprofen.

Can I take more than one antihistamine together?

Sometimes doctors recommend that people with severe itchy skin rash take 2 different antihistamines together for a few days.

As well as taking a non-drowsy antihistamine during the day (such as cetirizine or loratadine), your doctor may advise that you take a sedating antihistamine at night time if the itch is making it difficult to sleep.

Do not take 2 antihistamines together unless recommended by your doctor.

Can I take cetirizine with other hay fever treatments?

Yes, it’s fine to take cetirizine together with other hay fever treatments, for example steroid nasal sprays (such as Beconase, Rhinacort Aqua and Flixonase Nasules) or eye drops.

Can I take cetirizine at higher doses than on the packet?

Your doctor might suggest you or your child take a higher dose of cetirizine (up to 4 times the usual dose) for severe itchy skin rash or angioedema (swelling underneath the skin).

Taking high doses of cetirizine isn’t suitable for everyone though. Speak to your doctor if you think cetirizine isn't working for you.

Will it affect my fertility?

There’s no evidence that cetirizine affects male or female fertility.

Will it affect my contraception?

Cetirizine does not affect any type of contraception including the contraceptive pill and the morning after pill.

Can lifestyle changes relieve hay fever?

It will help if you don't spend too much time outside if the pollen count is high. Also:

Tips for when you're outside

Don't cut grass or walk on grass.
Wear wraparound sunglasses to stop pollen getting into your eyes.
Put Vaseline around your nostrils to help trap pollen.
Shower and change your clothes after you've been outside to wash off pollen.

Tips for when you're inside

Keep windows and doors shut as much as possible.
Vacuum regularly and dust with a damp cloth.
Don't keep fresh flowers in the house.
Don't smoke or be around smoke as it makes hay fever symptoms worse.