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

It's used to treat:

• hay fever
• conjunctivitis (red, itchy eye)
• eczema
• hives (urticaria)
• reactions to insect bites and stings
• some food allergies

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

Fexofenadine is available on prescription. It comes as tablets.

• It's usual to take fexofenadine once a day. Children sometimes 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.
• Fexofenadine is also called by the brand name Telfast.

Fexofenadine tablets can be taken by adults under the age of 65 and children aged 6 years and over.

Fexofenadine isn't recommended for people over 65 years old because there isn't much research on the medicine in this age group.

Talk to your pharmacist or doctor if you're over 65 and want to take fexofenadine.

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

• have had an allergic reaction to fexofenadine or any other medicines in the past
• have problems with your liver or kidneys
• have, or have ever had, heart problems
• have epilepsy or another health problem that puts you at risk of seizures
• are booked 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

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

How much to take

Fexofenadine comes as tablets (30mg, 120mg and 180mg).

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

• For hay fever - the usual dose for adults and children aged 12 years and over is 120mg once a day. The usual dose for children aged 6 to 11 years is 30mg twice a day. In this case, try to space the doses 10 to 12 hours apart.
• For hives - the usual dose for adults and children aged 12 years and over is 180mg once a day.

How to take it

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

If you're taking 120mg and 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

You may only need to take fexofenadine on a day you have symptoms, such as if you have 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, do not take a double dose to make up for a forgotten dose. Take the next dose at the usual time as prescribed by your doctor.

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?

Fexofenadine is generally very safe. Taking too much is unlikely to harm you.

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.

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 don't 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. Call a doctor straight away if you get a fast or irregular heartbeat.

Serious allergic reaction

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

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

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 doesn't help, talk to your doctor.
• headache - take an everyday painkiller like paracetamol or ibuprofen
• dry mouth - chew sugar-free gum or suck sugar-free sweets
• feeling dizzy - lie down until the dizziness passes, then get up slowly. Move slowly and carefully. Avoid coffee, cigarettes, alcohol and recreational drugs. If the dizziness doesn't get better within a couple of days, speak to your pharmacist or doctor.

Fexofenadine isn't normally recommended during pregnancy.

A similar antihistamine called loratadine is normally used first because there's more information to say that it's safe.

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

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

Fexofenadine and breastfeeding

There's not a lot of information on the use of fexofenadine during breastfeeding, so it's best not to take it.

It's usually safe to take similar antihistamines called loratadine and cetirizine while you're breastfeeding.

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

Some medicines and fexofenadine 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
• ketoconazole, a medicine to treat fungal infections
• erythromycin, an antibiotic
• ritonavir or lopinavir, medicines used to treat HIV infection
• rifampicin, an antibiotic
• indigestion remedies containing aluminium or magnesium - leave about 2 hours between the times that you take fexofenadine and your indigestion remedy
• 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 might be a problem taking some herbal remedies and supplements alongside fexofenadine, especially ones that cause sleepiness, a dry mouth, or make it difficult to pee.

Ask your pharmacist for advice.