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Fexofenadine - Brand names: Almerg, Telfast, Treathay

On this page

  1. About fexofenadine
  2. Key facts
  3. Who can and cannot take fexofenadine
  4. How and when to take fexofenadine
  5. Side effects
  6. How to cope with side effects of fexofenadine
  7. Pregnancy and breastfeeding
  8. Cautions with other medicines
  9. Common questions about fexofenadine

1. About fexofenadine

Fexofenadine is an antihistamine medicine that helps with the symptoms of allergies.

It's used to treat:

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

Fexofenadine comes as tablets.

It is available on prescription but you can also buy 120mg tablets from pharmacies and supermarkets. You can buy 180mg tablets for treating hives from pharmacies, or get them on prescription. Fexofenadine 30mg tablets for children are available on prescription only.

2. Key facts

  • You'll usually take fexofenadine once a day. Children aged 12 and under take it twice a day.
  • Fexofenadine is classed as a non-drowsy antihistamine, but some people still find it makes them feel quite sleepy.
  • Common side effects include headaches, feeling sleepy, dry mouth, feeling sick and dizziness.
  • Do not drink grapefruit juice, apple juice or orange juice while you're taking fexofenadine. It might make you more likely to get side effects.
  • It's best not to drink alcohol while you're taking fexofenadine as it can make you feel sleepy.

3. Who can and cannot take fexofenadine

Adults and children aged 6 years and over can take fexofenadine tablets.

Fexofenadine is not suitable for some people. To make sure it's safe for you, tell your doctor or pharmacist before taking fexofenadine if you:

  • have ever had an allergic reaction to fexofenadine or any other medicine
  • have problems with your liver or kidneys
  • have, or have ever had, heart problems
  • have epilepsy or another health condition that puts you at risk of seizures or fits
  • are due to have an allergy test – taking fexofenadine may affect the results, so you might need to stop taking it a few days before the test

4. How and when to take fexofenadine

If you or your child have been prescribed fexofenadine, follow your doctor's instructions about how and when to take it.


Fexofenadine comes as tablets in different strengths: 30mg, 120mg and 180mg.

How much you take depends on why you're taking it.

The usual dose for treating hay fever is:

  • 120mg once a day for adults and children aged 12 years and over
  • 30mg twice a day for children aged 6 to 11 years, with the doses spaced 10 to 12 hours apart

The usual dose for treating hives is 180mg once a day for adults and children aged 12 years and over.

Fexofenadine is not recommended for treating hives in children under 12.

How to take it

If you're taking 30mg fexofenadine tablets, you can take them with or without food.

If you're taking 120mg or 180mg fexofenadine tablets, take them before a meal.

Always take your fexofenadine tablets with a drink of water. Swallow them whole – do not chew them.

When to take it

Try to take fexofenadine tablets at about the same time every day. Choose a time that is easy to remember.

You may only need to take fexofenadine on a day you have symptoms, such as when you've been exposed to something you're allergic to, 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?

If you're taking fexofenadine once a day, take your forgotten dose as soon as you remember, unless it's nearly time for your next dose. In this case, skip the missed dose and take your next dose at the usual time.

Do not take 2 doses to make up for a forgotten dose.

If you forget to give a dose to a child who is taking fexofenadine 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 often forget doses, 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?

Fexofenadine is generally very safe. Taking more than your usual dose is unlikely to harm you.

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

5. Side effects

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

Common side effects

Common side effects of fexofenadine happen in more than 1 in 100 people.

Talk to your doctor or pharmacist if these side effects bother you or do not go away:

  • feeling sick (nausea)
  • feeling sleepy
  • headaches
  • dry mouth
  • feeling dizzy

Serious side effects

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

Urgent advice: Call 111 for advice now if:

  • you get a fast or irregular heartbeat

Serious allergic reaction

In rare cases, fexofenadine may cause a serious allergic reaction (anaphylaxis).

Immediate action required: Call 999 now if:
  • your lips, mouth, throat or tongue suddenly become swollen
  • you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
  • your throat feels tight or you're struggling to swallow
  • your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
  • you suddenly become very confused, drowsy or dizzy
  • someone faints and cannot be woken up
  • a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)

You or the person who's unwell may also have a rash that's swollen, raised, itchy, blistered or peeling.

These can be signs of a serious allergic reaction and may need immediate treatment in hospital.

These are not all the side effects of fexofenadine. For a full list, see the leaflet inside your medicine packet.


You can report any suspected side effect using the Yellow Card safety scheme.

Visit Yellow Card for further information.

6. How to cope with side effects of fexofenadine

What to do about:

  • feeling sick – stick to simple meals and do not eat rich or spicy food.
  • feeling sleepy – try a different non-drowsy antihistamine. If this does not help, talk to your doctor.
  • headache – make sure you rest and drink plenty of fluids. It's best not to drink alcohol. Take an everyday painkiller like paracetamol or ibuprofen.
  • dry mouth – chew sugar-free gum or suck sugar-free sweets
  • feeling dizzy – lie down until you do not feel dizzy anymore, then get up slowly. Move slowly and carefully. Avoid coffee, cigarettes, alcohol and recreational drugs. If the dizzy feeling does not get better within a couple of days, speak to your pharmacist or doctor.

7. Pregnancy and breastfeeding

Fexofenadine and pregnancy

Fexofenadine is not usually recommended if you're pregnant as there is not a lot of information about its use in pregnancy.

Other antihistamines may be more suitable as better safety information is available.

If you think that you need to take fexofenadine in pregnancy, talk to your doctor or pharmacist who will help you decide, or who may recommend other medicines for you.

Fexofenadine and breastfeeding

If your doctor or health visitor says your baby is healthy, you can take fexofenadine while breastfeeding.

There is very little information available, but it shows that only tiny amounts get into breast milk. It is unlikely to cause any side effects in your baby.

If you're breastfeeding or planning to breastfeed, talk to your doctor or pharmacist, as other antihistamines called loratadine and cetirizine might be better while you're breastfeeding.

If your baby is not feeding as well as usual, seems unusually sleepy, or seems irritable, or if you have any other concerns about your baby, talk to your doctor, pharmacist, health visitor or midwife.

Non-urgent advice: Tell your doctor if you're:

  • trying to get pregnant
  • pregnant
  • breastfeeding

For more information about how fexofenadine can affect you and your baby during pregnancy, visit the Best Use of Medicines in Pregnancy (BUMPS) website.

8. Cautions with other medicines

Some medicines and fexofenadine can affect each other and increase the chances of you having side effects.

Check with your pharmacist or doctor if you're taking:

  • ketoconazole, a medicine to treat fungal infections
  • dronedarone, a medicine used in people who have had cardioversion to control their heart rate
  • erythromycin, an antibiotic
  • filgotinib or leflunomide, medicines to treat arthritis
  • letermovir, a medicine used in people who have had a stem cell transplant
  • pibrentasvir or velpatasvir, medicines to treat hepatitis C infection
  • rifampicin, an antibiotic
  • teriflunomide, a medicine to treat multiple sclerosis
  • indigestion remedies containing aluminium or magnesium – leave about 2 hours between taking fexofenadine and taking your indigestion remedy
  • medicines to treat cancer
  • any medicine that makes you drowsy, gives you a dry mouth, or makes it difficult for you to pee – taking fexofenadine might make these side effects worse

Mixing fexofenadine with herbal remedies and supplements

There's very little information about taking herbal remedies and supplements with fexofendadine. There might be a problem taking some herbal remedies and supplements with it, especially ones that cause sleepiness or a dry mouth, or make it difficult to pee.

Ask your pharmacist for advice.

Important: Medicine safety

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

9. Common questions about fexofenadine

How does fexofenadine work?

Fexofenadine is a type of 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, a running or blocked nose, sneezing and skin rashes.

Fexofenadine blocks the effects of histamine and reduces these symptoms.

When will I feel better?

You should start to feel better within 1 to 2 hours.

How long should I take fexofenadine for?

It depends on why you're taking fexofenadine.

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

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

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

Is it safe to take fexofenadine for a long time?

Fexofenadine is unlikely to do you any harm if you take it for a long time. But it's best to take it 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 fexofenadine as it can make you feel sleepy.

Is there any food or drink I need to avoid?

Do not drink grapefruit juice, orange juice or apple juice while taking fexofenadine. It might make you more likely to have side effects.

Can I drive or ride a bike with it?

Fexofenadine is classed as a non-drowsy antihistamine, but it's still possible to feel sleepy after taking it.

If you're taking fexofenadine for the first time, see how it makes you feel before driving, cycling, or using heavy machinery or tools.

It's an offence to drive a car if your ability to drive safely is affected. It's your responsibility to decide if it's safe to drive. If you're in any doubt, do not drive.

Talk to your doctor or pharmacist if you're unsure whether it's safe for you to drive while taking fexofenadine. GOV.UK has more information on the law on drugs and driving.

Does fexofenadine cause weight gain?

Fexofenadine is not known to cause weight gain.

What's the difference between fexofenadine and other antihistamines?

Fexofenadine is known as a non-drowsy antihistamine. That's because it's less likely to make you feel sleepy than drowsy (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 fexofenadine and other non-drowsy antihistamines?

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

But fexofenadine seems to be less likely to make you feel sleepy than other non-drowsy antihistamines.

If one non-drowsy antihistamine has not worked for you, it's worth trying another one.

Can I take it with painkillers?

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

Can I take 2 different antihistamines together?

Sometimes doctors recommend that people with a 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 fexofenadine, cetirizine or loratadine), your doctor may suggest that you take a sedating antihistamine at night time if the itching is making it difficult to sleep.

Do not take 2 antihistamines together unless your doctor advises you to.

Can I take fexofenadine with other hay fever treatments?

Yes, it's fine to take fexofenadine together with some other hay fever treatments, including steroid nasal sprays (such as Beconase, Rhinacort Aqua and Flixonase Nasules) or eye drops.

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

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

Taking high doses of fexofenadine is not suitable for everyone. Speak to your doctor if you do not think your prescribed dose of fexofenadine is working for you.

Will it affect my fertility?

There's no evidence to suggest that taking fexofenadine will reduce fertility in either men or women.

But speak to a pharmacist or your doctor before taking it if you're trying to get pregnant.

Will it affect my contraception?

Fexofenadine does not affect any type of contraception, including the combined pill and emergency contraception.

Can lifestyle changes relieve hay fever?

It'll help if you do not spend too much time outside if the pollen count is high.

Tips for when you're outside

  • Do not 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 have 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.
  • Do not keep fresh flowers in the house.
  • Do not smoke or be around smoke as it makes hay fever symptoms worse.

Page last reviewed: 14 October 2021
Next review due: 14 October 2024