Rabeprazole 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.

Rabeprazole is also taken to prevent and treat stomach ulcers. Sometimes, rabeprazole is taken for a rare illness caused by a tumour in the pancreas or gut called Zollinger-Ellison syndrome.

Rabeprazole is only available on prescription. It comes as tablets.

• It's usual to take rabeprazole once a day in the morning.
• Common side effects include headaches, diarrhoea, feeling or being sick, constipation, stomach pain or wind. These tend to be mild and go away when you stop taking the medicine.
• Rabeprazole isn't usually recommended during pregnancy or while breastfeeding.
• You can drink alcohol with rabeprazole but alcohol may make your symptoms worse.
• Rabeprazole is called by the brand name Pariet.

Rabeprazole can be taken by adults but it is not generally recommended in pregnancy or while breastfeeding. Rabeprazole 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 rabeprazole or any other medicines in the past
• are due to have an endoscopy

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

It's usual to take rabeprazole once a day, first thing in the morning.

If your doctor prescribes rabeprazole twice a day, take 1 dose in the morning and 1 dose in the evening.

It's best to take rabeprazole before a meal. Swallow tablets whole with a drink of water.

How much will I take?

Each tablet contains 10mg or 20mg of rabeprazole.

The usual dose to treat:

• heartburn, acid reflux and gastro-oesophageal reflux disease is 10mg to 20mg a day
• stomach ulcers is 20mg a day
• Zollinger-Ellison syndrome is 60mg to 120mg a day

Will my dose go up or down?

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

Depending on the reason you take rabeprazole, 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?

Depending on your illness, you may only take it for a few weeks or months. Sometimes you might need to take it for longer, even many years.

Some people don't need to take rabeprazole every day and take it only when they have symptoms. Once you feel better (often after a few days or weeks), you can stop taking it. Taking rabeprazole in this way is not suitable for everyone though. 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 your next dose is due in less than 12 hours, in which case skip the missed dose. Then take your next dose as normal.
• twice a day - take the missed dose as soon as you remember, unless your next dose is due in less than 4 hours, in which case skip the missed dose. Then take your next dose as normal

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 1 or 2 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:

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

Most people who take rabeprazole 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 rabeprazole.

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

Serious side effects

Some of these serious side effects are more common than others. 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 rabeprazole for a long time
• stomach pain that gets worse, yellow skin (or the whites of your eyes turn yellow) or dark pee. These could be signs of liver problems
• pain when you pee, peeing less, lower back pain, swollen ankles, and rash or fever. These could be signs of a kidney problem
• frequent infections, such as a sore throat or high temperature (38C or above), or ulcers in your mouth or throat

Serious allergic reaction

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

These are not all the side effects of rabeprazole. 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. Headaches should usually go away after the first week of taking rabeprazole. Talk to your doctor if they last longer than a week or are severe.
• feeling sick - it may help if you to avoid rich or spicy food while you're taking rabeprazole.
• diarrhoea or being sick (vomiting) - drink plenty of water by having small, frequent sips to avoid dehydration. Signs of dehydration include peeing less than usual or having strong-smelling pee.
• constipation - get more fibre into your diet such as fresh fruit and vegetables and cereals, and drink plenty of water. Try to exercise, 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 the symptoms of wind.

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

A medicine called omeprazole, which is similar to rabeprazole, is safe in pregnancy. However, if you're pregnant, it's better to try to treat symptoms of acid reflux and heartburn without taking a medicine.

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

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, your doctor may prescribe omeprazole to help ease your symptoms.

Rabeprazole and breastfeeding

It is not known if rabeprazole passes into breast milk.

A medicine called omeprazole, which is similar to rabeprazole, 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 rabeprazole and make it more likely that you will have side effects.

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

• digoxin (a heart medicine)
• antifungal medicines such as itraconazole, ketoconazole or posaconazole
• methotrexate (for cancer and conditions like psoriasis and rheumatoid arthritis)
• HIV medicines
• rifampicin (an antibiotic)
• antidepressants, such as fluvoxamine

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

Mixing rabeprazole with herbal remedies and supplements

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