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Proton pump inhibitors reduce the amount of acid made by your stomach. They are commonly used to treat acid reflux and ulcers of the stomach and part of the gut called the duodenum. Most people who take a proton pump inhibitor do not develop any side-effects.

Proton pump inhibitors (PPIs) are a group (class) of medicines that work on the cells that line the stomach, reducing the production of acid. They include esomeprazole, lansoprazole, omeprazole, pantoprazole and rabeprazole, and have various different brand names.

PPIs are commonly used:

PPIs usually work very well to reduce stomach acid and to treat the above conditions. They have made a big impact on the quality of life of many people with these conditions since they first became available in the 1980s. They are commonly prescribed.

Upper gastrointestinal tract and acid

Upper GI Tract and acid

Your stomach normally produces acid to help with the digestion of food and to kill germs (bacteria). This acid is corrosive so your body produces a natural mucous barrier which protects the lining of the stomach from being worn away (eroded).

In some people this barrier may have broken down allowing the acid to damage the stomach, causing an ulcer. In others there may be a problem with the muscular band at the top of the stomach (the sphincter) that keeps the stomach tightly closed. This may allow the acid to escape and irritate the gullet (oesophagus). This is called 'acid reflux' which can cause heartburn and/or inflammation of the gullet (oesophagitis).

PPIs stop cells in the lining of the stomach producing too much acid. This can help to prevent ulcers from forming or assist the healing process. By decreasing the amount of acid, they can also help to reduce acid reflux-related symptoms such as heartburn.

They are called 'proton pump inhibitors' because they work by blocking (inhibiting) a chemical system called the hydrogen-potassium adenosine triphosphatase enzyme system (otherwise known as the 'proton pump'). This chemical system is found in the cells in the stomach lining that make stomach acid.

You can buy omeprazole, lansoprazole and pantoprazole over the counter at pharmacies. Rabeprazole still requires a prescription. However, if you need to use a PPI for more than four weeks you should consult your doctor.

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Your doctor will advise you of the dose needed and how often you should take it. Some of these medicines need to be taken in a certain way, such as on an empty stomach. Therefore, read the leaflet that comes with your particular brand for further information.

Generally, PPIs are well absorbed by the body and may provide quick relief for some problems. For example, heartburn caused by acid reflux. However, if you are taking them for other reasons, such as to heal an ulcer, it may take longer for the medicines to have an underlying effect.

This can vary depending on the reason you are taking a PPI. So, speak with your doctor for advice. For example, in some cases your doctor may prescribe a PPI that you only take 'as required' to relieve your symptoms, rather than every day. In some cases a regular dose taken each day is advised.

It is possible that your symptoms might come back if you stop your medication. If this happens, see your doctor again.

PPIs may not be suitable for some people - for example, people with certain liver problems. Breastfeeding or pregnant mums should avoid them apart from omeprazole which is deemed to be safe. A full list of individuals who should not take a PPI is included with the information leaflet that comes in the medicine packet. If you are prescribed or buy a PPI, read this to be sure you are safe to take it.

Most people who take a PPI do not have any side-effects. However, side-effects occur in a small number of users. The most common side-effects are:

  • Constipation
  • Diarrhoea
  • Wind (flatulence)
  • Headaches
  • Feeling sick (nausea)
  • Tummy (abdominal) pain
  • Being sick (vomiting)

Recent research has found a link between long-term treatment with PPIs and gastric cancer, although further studies are needed. A group of medicines known as H2 blockers are therefore preferred for long-term use. Some people find that only PPIs control their symptoms. Each individual needs to take advice from their doctor, and weigh up the risks and benefits.

For a full list of possible side-effects and cautions, see the leaflet that comes in the packet with your particular brand.

In particular: tell your doctor if you are taking the blood-thinning medicine warfarin, or a medicine for epilepsy, called phenytoin (Epanutin®), or medicines called digoxin, methotrexate or cilostazol. Taking a PPI can affect how well these medicines work, or can even cause serious 'drug reactions'. Also, lansoprazole possibly affects how well oral contraceptives might work. Discuss this with your doctor if it is relevant to you.

If you are taking antacids you should try to avoid taking them at the same time as you take your other medication, including PPIs. This is because antacids can affect how well your medication is absorbed.

How to use the Yellow Card Scheme

If you think you have had a side-effect to one of your medicines you can report this on the Yellow Card Scheme. You can do this online at

The Yellow Card Scheme is used to make pharmacists, doctors and nurses aware of any new side-effects that medicines or any other healthcare products may have caused. If you wish to report a side-effect, you will need to provide basic information about:

  • The side-effect.
  • The name of the medicine which you think caused it.
  • The person who had the side-effect.
  • Your contact details as the reporter of the side-effect.

It is helpful if you have your medication - and/or the leaflet that came with it - with you while you fill out the report.

You should consult your doctor if your symptoms worsen, or if you experience any of the following problems which can indicate a serious gut disorder:

  • Bringing up (vomiting) blood. This may be obviously fresh blood, but altered blood in vomit can look like ground coffee. Doctors call this 'coffee-ground vomit'.
  • Blood in your stools (faeces). This may be obvious blood, or it may just make your stools black.
  • Unintentional weight loss.
  • Difficulty swallowing, including food getting stuck in the gullet (oesophagus).
  • Persistent tummy (abdominal) pain or persistent vomiting.


H2 Blockers

Further reading and references