Esomeprazole reduces the amount of acid your stomach makes.

It's used for heartburn, acid reflux and gastro-oesophageal reflux disease (GORD) - GORD is when you keep getting acid reflux. It's also taken to prevent and treat stomach ulcers.

Sometimes, esomeprazole is taken for a rare illness caused by a tumour in the pancreas or gut called Zollinger-Ellison syndrome.

Esomeprazole also comes mixed with naproxen, a medicine that reduces inflammation and pain in joints and muscles.

Esomeprazole comes as capsules, tablets, granules and as a liquid.

All types of esomeprazole are available on prescription. You can also buy the lowest-strength 20mg tablets and capsules from pharmacies.

• It's usual to take esomeprazole once a day in the morning.
• Common side effects include headache, diarrhoea and stomach pain. These tend to be mild and go away when you stop taking the medicine.
• Esomeprazole is called by the brand names Nexium, Nexium Control, Emozul and Ventra.
• When esomeprazole is mixed with naproxen it's called the by brand name Vimovo.
• If you've bought esomeprazole without a prescription and your symptoms don't improve after 2 weeks, see a doctor before taking any more.

Esomeprazole can be taken by adults. Children should only have esomeprazole if their doctor prescribes it.

Esomeprazole isn't suitable for some people. To make sure that it is safe for you, tell your doctor if you:

• have had an allergic reaction to esomeprazole or any other medicines in the past
• have liver problems
• cannot absorb certain types of sugars including glucose or sucrose
• are due to have an endoscopy

Ask your doctor if you should stop taking esomeprazole a few weeks before your endoscopy. This is because esomeprazole may hide some of the problems that would usually be spotted during an endoscopy.

It's usual to take esomeprazole once a day, first thing in the morning. You can take it with or without food.

If you take esomeprazole twice a day, take one dose in the morning and one dose in the evening.

Swallow tablets whole with a drink of water. If you have problems swallowing tablets, you can put them in a glass of water. Stir until the tablets start to break up, then drink straight away.

If you have problems swallowing capsules, you can open up esomeprazole capsules and empty the contents into a glass. Mix with some water and drink straight away. Fill the glass with water again, and drink that as well to make sure there's no medicine left at the bottom of the glass.

If your child is under 12 years old, their doctor may prescribe esomeprazole granules which come in sachets. Empty the granules into a glass and mix with some water, then encourage them to drink it straight away.

How much to take

Each tablet or capsule contains 20mg or 40mg. Each sachet contains 10mg.

The usual dose to treat:

• heartburn and acid reflux is 20mg a day
• gastro-oesophageal reflux disease is 20mg to 40mg a day
• stomach ulcers is 20mg a day
• Zollinger-Ellison syndrome is 80mg a day - this can increase to 160mg a day depending on how well it works for you

Doses are usually lower for children and people with liver problems.

Will my dose go up or down?

Sometimes your doctor will increase your dose if it isn't working well enough.

Depending on the reason you take esomeprazole, you may take a higher dose to begin with, usually for a month or two. After this, your doctor may recommend that you take a lower dose.

How long will I take it for?

If you have bought the medicine yourself from a pharmacy or supermarket, tell your doctor if you feel no better after taking esomeprazole for 2 weeks. They may want to do tests to find out what's causing your symptoms or change you to a different medicine.

If you take it on prescription, you may only take it for a few weeks or months, depending on your illness. Sometimes your doctor may advise you to take it for longer, even many years.

Your doctor may suggest taking esomeprazole only when you have symptoms. This means you won't have to take it every day. Once you feel better, you can stop taking it - often after a few days or weeks. Taking esomeprazole this way isn't suitable for everyone. Speak to your doctor about what's best for you.

What if I forget to take it?

If you usually take it:

• once a day, take the missed dose as soon as you remember, unless it's less than 12 hours until your next dose - in which case skip the missed dose.
• twice a day, take the missed dose as soon as you remember, unless it's less than 4 hours until your next dose - in which case skip the missed dose.

Do not take a double dose to make up for a forgotten dose. 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 remember your medicine.

What if I take too much?

It is very unlikely that taking one or two extra doses by accident will cause any problems. However, you should check with your doctor if you have taken too much and have any of these symptoms:

• feeling sweaty
• a fast heartbeat
• feeling sleepy
• blurred vision
• feeling confused or agitated

Most people who take esomeprazole do not have any side effects. If you do get a side effect, it is usually mild and will go away when you stop taking esomeprazole.

Common side effects

Common side effects may 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:

• headaches
• diarrhoea
• feeling or being sick (nausea or vomiting)
• constipation
• stomach pain or wind

Serious side effects

Serious side effects happen in less than 1 in 1,000 people. Call a doctor straight away if you have:

• joint pain and abnormal changes in your skin, especially in parts of your body exposed to the sun, such as a red, raised rash on your arms that can spread, blisters, or a red rash on your cheeks and nose. These can be signs of a rare condition called subacute cutaneous lupus erythematosus. This can happen even if you've been taking esomeprazole for a long time.
• yellow skin, dark pee and tiredness. These can be signs of liver problems.

Serious allergic reaction

In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to esomeprazole.

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

What to do about:

• headaches - make sure you rest and drink plenty of fluids. Do not drink too much alcohol. Ask your pharmacist to recommend a painkiller.
• diarrhoea - drink plenty of water to avoid dehydration. Signs of dehydration include peeing less than usual or having strong-smelling pee.
• feeling or being sick (nausea or vomiting) - try taking esomeprazole with or after a meal or snack. It may also help if you don't eat rich or spicy food while you're taking this medicine.
• constipation - eat more high-fibre foods such as fresh fruit and vegetables and cereals, and drink plenty of water. Try to exercise more regularly, for example, by going for a daily walk or run. If this doesn't help, talk to your pharmacist or doctor.
• stomach pain or wind - steer clear of foods that cause wind like lentils, beans and onions. It might also help to eat smaller and more frequent meals, eat and drink slowly, and exercise regularly. Some pharmacy remedies, such as simethicone may relieve symptoms of wind.

Esomeprazole isn't usually recommended during pregnancy as there's no firm evidence it's safe.

A medicine called omeprazole, which is similar to esomeprazole, is safe in pregnancy.

However, if you're pregnant, it's always better to try to treat your symptoms without taking a medicine.

Your doctor or midwife may suggest eating smaller meals more often and avoiding fatty and spicy food.

They may also suggest raising the head of your bed 10 to 20cm by putting something under your bed or mattress, so that your chest and head are above your waist. This helps stop stomach acid travelling up towards your throat.

If these lifestyle changes don't work, you may be recommended omeprazole to help ease your symptoms.

Esomeprazole and breastfeeding

Esomeprazole may get into breast milk, but it's not known whether it harms the baby. A medicine called omeprazole, which is similar to esomeprazole, is safe to take while breastfeeding. Speak to your doctor to discuss what is best for you and your baby.

Some medicines can interfere with esomeprazole and make you more likely to have side effects.

Tell your doctor if you're taking these medicines before you start taking esomeprazole:

• digoxin (a heart medicine)
• cilostazol (a medicine used to treat painful legs caused by poor circulation)
• antifungal medicines such as itraconazole, ketoconazole or posaconazole
• methotrexate (a medicine used to treat cancer and conditions like psoriasis and rheumatoid arthritis)
• HIV medicines
• phenytoin (an anti-epilepsy medicine)
• rifampicin (an antibiotic)
• blood thinning medicines, such as clopidogrel
• citalopram, escitalopram, clomipramine or imipramine (antidepressants)
• tacrolimus (a medicine used for eczema or to prevent organ rejection after a transplant)

These are not all the medicines that may not mix well with esomeprazole. For a full list see the leaflet inside your medicines packet.

Mixing esomeprazole with herbal remedies and supplements

Do not take St John's wort, the herbal remedy for depression, while you're taking esomeprazole. St John's wort may stop esomeprazole working as well as it should.