Lansoprazole to reduce stomach acid Zoton FasTab, Prevacid

Last updated by Peer reviewed by Sid Dajani
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Lansoprazole reduces the amount of acid produced in your stomach.

Take your doses 30 minutes before breakfast when your stomach is empty. If you are asked to take two doses daily, take your first dose 30 minutes before breakfast and your second dose in the evening.

The most common side-effects are stomach upset and headache. These effects are generally mild and do not last long.

Type of medicineProton pump inhibitor
Used forGastric ulcer; duodenal ulcer; gastro-oesophageal reflux disease; Helicobacter pylori infection; Zollinger-Ellison syndrome; acid-related dyspepsia
Also called (UK)Zoton FasTab®
Also called (USA)Prevacid®; Prevacid SoluTab®
Available asCapsules, orodispersible (melt-in-the-mouth) tablets

Acid is produced naturally in your stomach to help you digest food and to kill bacteria. This acid is irritant so your body produces a natural mucous barrier which protects the lining of your stomach. In some people, this barrier can break down allowing the acid to damage the stomach, causing inflammation, ulcers and other conditions. Other people can have a problem with the muscular band at the top of the stomach that keeps the stomach tightly closed. This may allow the acid to escape and irritate the oesophagus, causing heartburn. This is often referred to as 'acid reflux'.

Proton pump inhibitors such as lansoprazole stop cells in the lining of the stomach from producing too much acid. This helps to prevent ulcers from forming, or assists the healing process where damage has already occurred. By decreasing the amount of acid, they can also help to reduce the symptoms of acid reflux disease, such as heartburn.

Lansoprazole is also given as one part of a treatment to get rid of Helicobacter pylori, a bacterium found in the stomach, which can cause ulcers.

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking lansoprazole it is important that your doctor or pharmacist knows:

  • If you are pregnant, trying for a baby or breastfeeding.
  • If you have any problems with the way your liver works.
  • If you have any of the following symptoms: difficulty swallowing, loss of blood, weight loss, or if you are being sick (vomiting).
  • If you have ever had an allergic reaction to a medicine.
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.
  • Before you start this treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about lansoprazole and will provide you with a full list of the side-effects which you may experience from taking it.
  • Take lansoprazole exactly as your doctor tells you to. There are different strengths of tablets and capsules available so your doctor will tell you which is right for you. It is usually taken once a day in the morning. If you are taking it for either Helicobacter pylori eradication or for Zollinger-Ellison syndrome, it is likely you will be asked to take two doses a day. Your doctor will tell you which dose is right for you and the directions will also be on the label of the pack to remind you.
  • Lansoprazole should be taken at least 30 minutes before a meal, which is usually breakfast. This is because your body absorbs less lansoprazole after you have eaten a meal, so the medicine is less effective. If you have been asked to take two doses daily, take your first dose 30 minutes before breakfast and your second dose in the evening.
  • If you have been given capsules to take, swallow the capsule with a drink of water. Do not chew, crush or open the capsule before you swallow.
  • If you have been given orodispersible tablets (Zoton FasTabs®), you can swallow the tablet with a drink of water as usual, or you can place it on your tongue and allow it to 'melt' there before you swallow. Alternatively, you can stir it into a small amount of water to take it.
  • Do not take indigestion remedies during the two hours before or during the two hours after you take lansoprazole as they can interfere with the way lansoprazole is absorbed by your body.
  • If you forget to take a dose at your usual time, you can take it when you remember (unless it is nearly time for your next dose, in which case leave out the missed dose). Do not take two doses at the same time to make up for a forgotten dose.
  • Try to keep your regular appointments with your doctor. This is so your progress can be checked. If you are taking lansoprazole on a long-term basis your doctor will want to review your treatment at least once a year to make sure it is still right for you.
  • Typical courses of treatment last for one or two weeks if you are taking lansoprazole for Helicobacter pylori eradication. If you are taking it for acid-related dyspepsia, your treatment will typically last for two to four weeks. It will last for around one or two months if it is for an ulcer. For acid reflux or Zollinger-Ellison syndrome, your treatment will last for as long as is necessary to control your symptoms.
  • Some foods may make your symptoms worse. Foods and drinks that have been suspected of this include peppermint, tomatoes, chocolate, spicy foods, hot drinks, coffee, and alcoholic drinks. If it seems that a food is aggravating your symptoms, try avoiding it for a while to see if your symptoms improve. Also, try avoiding eating large meals, as these can make your symptoms worse too.
  • If you are overweight, it puts extra pressure on your stomach and encourages the symptoms of acid reflux. Losing some weight and eating a healthy balanced diet may help you.
  • Smoking increases the amount of acid produced by the stomach and may make your symptoms worse. If you are a smoker, speak with your doctor or pharmacist about how to quit.
  • Recent studies suggest that there may be a slight increase in the risk of bone fractures when proton pump inhibitors like lansoprazole are taken for longer than a year. If this affects you, your doctor will check that you are taking enough vitamin D and calcium to reduce this risk.
  • If you buy any medicines 'over-the-counter', always check with a pharmacist that they are safe to take alongside your other medicines.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with lansoprazole. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Common lansoprazole side-effects (these affect fewer than 1 in 10 people)What can I do if I experience this?
Stomach upset (such as feeling sick (nausea), stomach ache, or wind)Stick to simple meals - avoid rich or spicy foods
DiarrhoeaDrink plenty of water. If it continues or becomes severe, let your doctor know
ConstipationTry to eat a well-balanced diet and drink several glasses of water each day
HeadacheDrink plenty of water and ask your pharmacist to recommend a suitable painkiller. If the headaches continue, let your doctor know
Feeling dizzy or tiredDo not drive and do not use tools or machines until you feel better
Dry mouth or throat, itchy skin rashIf any of these become troublesome, let your doctor know

Important: long-term use of lansoprazole (for at least three months) may lead to low levels of magnesium in your blood. Initial signs this might be happening include feeling tired, dizzy or confused and an irregular heartbeat (palpitations). Let your doctor know if you think this applies to you.

If you experience any other symptoms which you think may be due to the medicine, speak with your doctor or pharmacist for further advice.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

If you are having an operation or any dental treatment, tell the person carrying out the treatment which medicines you are taking.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

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