Lansoprazole reduces the amount of acid your stomach makes. It's used for indigestion, heartburn and acid reflux and gastroesophageal-reflux-disease (GORD). Lansoprazole is also taken to prevent and treat stomach ulcers.

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

Lansoprazole is available only on prescription. It comes as capsules, tablets and as a liquid that you swallow (made to order).

• It's usual to take lansoprazole once a day in the morning.
• For severe illness, you can take it twice a day - in the morning and in the evening.
• Common side effects include headache, diarrhoea and stomach pain. These tend to be mild and go away when you stop taking the medicine.
• Lansoprazole is called by the brand name Zoton FasTabs.

Lansoprazole can be taken by adults. It can also be taken by children when prescribed by a doctor.

Lansoprazole isn't suitable for some people.

To make sure lansoprazole is safe for you, tell your doctor if you:

• have had an allergic reaction to lansoprazole or any other medicines in the past
• have liver problems
• are due to have an endoscopy

If you are having an endoscopy, ask your doctor if you should stop taking lansoprazole a few weeks before your procedure. This is because lansoprazole may hide some of the problems that would usually be spotted during an endoscopy. Lansoprazole is generally not recommended in pregnancy or while breastfeeding.

It's usual to take lansoprazole once a day - first thing in the morning.

If you take lansoprazole twice a day, take 1 dose in the morning and 1 dose in the evening.

Lansoprazole works best if you take it 30 minutes before a meal or snack. That's because food slows down lansoprazole getting into your system.

How much to take

The usual dose to treat:

• indigestion is 15mg to 30mg a day
• acid reflux is 15mg to 30mg a day
• stomach ulcers is 15mg to 30mg a day
• Zollinger-Ellison syndrome is 60mg a day - this can increase to 120mg a day depending on how well it works for you

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

Tablets and capsules

Swallow tablets and capsules whole with a glass of water or juice.If you have problems swallowing capsules, you can open lansoprazole capsules and mix the granules inside with a little water or fruit juice, or sprinkle them onto soft food, such as yogurt or apple puree, to help you swallow them.

Lansoprazole also comes as a dispersible tablet that melts in your mouth. Each tablet or capsule contains 15mg or 30mg of lansoprazole.

Liquid lansoprazole

Liquid lansoprazole can be prescribed and made to order for children and people who cannot swallow capsules or tablets. It will come with a syringe or spoon to help you take the right amount. 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.

Will my dose go up or down?

Sometimes your doctor will increase your dose of lansoprazole if it isn't working well enough. Depending on the reason you take lansoprazole, 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 need to 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 lansoprazole 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 lansoprazole in this way is not suitable for everyone. Discuss with your doctor what is 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 is within 12 hours of your next dose in which case skip the missed dose
• twice a day, take the missed dose as soon as you remember, unless it is within 4 hours of 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 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 lansoprazole 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 lansoprazole.

Common side effects

These 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
• feeling sick
• diarrhoea or being sick (vomiting)
• stomach pain
• constipation
• wind
• itchy skin rashes
• feeling dizzy or tired
• dry mouth or throat

Serious side effects

Serious side effects are rare and happen in less than 1 in 1,000 people.

Call a doctor straight away if you have:

• joint pain along with a red skin rash, especially in parts of your body exposed to the sun, such as your arms, 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 lansoprazole for a long time
• stomach pain that seems to be getting worse - this can be a sign of an inflamed liver or pancreas

Serious allergic reaction

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

These are not all the side effects of lansoprazole. 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 lansoprazole. Talk to your doctor if they last longer than a week or are severe.
• feeling sick - it may help if you don't eat rich or spicy food while you're taking lansoprazole.
• 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. Do not take any other medicines to treat diarrhoea or vomiting without speaking to a pharmacist or doctor.
• stomach pain - try to rest and relax. It can help to eat and drink slowly and have smaller and more frequent meals. Putting a heat pad or covered hot water bottle on your stomach may also help. If you are in a lot of pain, speak to your pharmacist or doctor.
• 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.
• wind - steer clear of foods that cause wind like lentils, peas, 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 help relieve the symptoms of wind.
• itchy skin rashes - it may help to take an antihistamine which you can buy from a pharmacy. Check with the pharmacist to see what type is suitable for you.
• feeling dizzy or tired - if lansoprazole makes you feel dizzy or tired, stop what you're doing and sit or lie down until you feel better. Do not drive or use tools or machinery if you're feeling tired. Do not drink alcohol as it will make you feel worse.
• dry mouth or throat - chew sugar-free gum or sugar-free sweets.

Lansoprazole isn't usually recommended during pregnancy and while breastfeeding.

If you're pregnant, it's always better to try to treat your indigestion without taking a medicine.

Your doctor or midwife will first advise that you try to ease your symptoms by eating smaller meals more often, and avoiding fatty and spicy foods.

They may also suggest that you raise 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 lifestyle changes don't work, you may be recommended a medicine to help ease your symptoms.

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

Lansoprazole and breastfeeding

Lansoprazole may get into breast milk, but it's not known whether it harms the baby.

Talk to your doctor about the pros and cons of taking this medicine while you're breastfeeding.

A medicine called omeprazole, which is a similar to lansoprazole is safe to take while breastfeeding.

Some medicines and lansoprazole can interfere with each other and make it more likely that you will have side effects.

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

• digoxin (a heart medicine)
• antifungal medicines such as itraconazole, ketoconazole or posaconazole
• methotrexate (treats psoriasis and rheumatoid arthritis)
• HIV medicines
• phenytoin (an anti-epilepsy medicine)
• rifampicin (an antibiotic)
• blood thinning medicines, such as clopidogrel
• fluvoxamine (an antidepressant)

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

Mixing lansoprazole with herbal remedies and supplements

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