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Indigestion - Module 135

Indigestion is a very common problem, but one that can usually be managed OTC and with some simple lifestyle changes

In this article you will learn: The symptoms of indigestion and when patients should be referred The symptoms of indigestion and when patients should be referredThe actions and side effects of different types of anti-indigestion products The symptoms of indigestion and when patients should be referredWhen to recommend different types of indigestion medication The symptoms of indigestion and when patients should be referredExtra advice you can give indigestion sufferers to help minimise their symptoms.

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Indigestion is a very common problem, but one that can usually be managed OTC and with some simple lifestyle changes One afternoon in the pharmacy, you notice a woman in her 30s looking at the indigestion medicines on the shopfloor. She has been there for a few minutes, picking up various products and reading the packaging, but you sense that she is no nearer a decision. You approach her and ask if she needs any help. The woman says that she has been feeling a bit uncomfortable after meals, particularly in the evening, with what she describes as stomach ache and a burning sensation in her chest. After asking a few questions (see ‘when to refer' box) you diagnose heartburn, so you start thinking about what would be the best product to recommend.


Antacids work by neutralising stomach acid. They usually comprise a mixture of magnesium and aluminium salts, plus calcium carbonate or sodium bicarbonate. Some also contain an alginate, which forms a barrier layer over the stomach contents to prevent them from moving upwards from the stomach into the oesophagus. Other products contain: bismuth compounds, which are thought to act by coating the stomach lining; dimeticone, to help with trapped wind; and peppermint oil, which may be included for its calming effect on the stomach. Most antacids are available as both tablets and liquids – liquids tend to get to work quicker, but the effects of tablets tend to last longer.   Antacids should be taken when required after meals or at bedtime. Some customers may ask about taking an antacid before a meal if they know they are going to get indigestion symptoms, but this is not usually recommended as the effect will usually only last between 20 minutes and one hour if taken on an empty stomach (compared with two to three hours if taken with or after food). Antacids may cause mild side effects, such as diarrhoea (if the product contains magnesium salts) or constipation (if aluminium salts). Products containing bismuth can cause darkening of the stools or tongue, but this is harmless and will resolve once the patient stops taking the product. It is important to check whether anyone requesting an antacid is taking any other medicines, such as iron supplements or tetracycline antibiotics. This is because antacids can stop these drugs being properly absorbed by the body. Similarly, if a patient says they have, or are on medication for, high blood pressure or a heart condition, check your product recommendation with your pharmacist as these patients must avoid antacids that contain a large amount of sodium.

Proton pump inhibitors

Proton pump inhibitors (PPIs), such as omeprazole, reduce the amount of acid produced by the stomach, and may be useful for people with severe or recurrent indigestion who find that antacids do not resolve their symptoms. However, it is important to remember that while a PPI will prevent indigestion occurring or worsening, it will not ease symptoms in the same way that an antacid will. Only one PPI is available over the counter – omeprazole. It may only be sold for short-term use by adults aged over 18 years. Other PPIs are available on prescription, and – like omeprazole – can be taken long term if a GP decides it is required. The recommended dose is two tablets before food, then one tablet each day thereafter if symptoms continue, increasing to two tablets if the discomfort improves but does not resolve completely. The side effects of PPIs are usually mild and stop once the treatment is discontinued. Headache and GI discomfort (diarrhoea, constipation, vomiting, stomach pain, flatulence), are among the most common. Few other drugs interact with PPIs, but ask your pharmacist if a patient says they are taking any other medicine, particularly the anti-epileptic phenytoin or the blood thinner warfarin.


H2-antagonists work by lowering the amount of acid in the stomach so can be helpful if antacids have proved ineffective. Much like PPIs, they are good at preventing symptoms recurring or worsening, but do not offer rapid symptom relief in the way antacids do. There are two H2-antagonists available to buy – ranitidine and famotidine – both in tablet form. One tablet should be taken at onset of symptoms, then another within a couple of hours or later in the day if the symptoms have not resolved or have recurred. No more than two tablets should be taken in 24 hours, and OTC H2-antagonists should only be taken short-term.

Side effects are rare but may include diarrhoea, headache and dizziness. Interactions are very uncommon, but it is sensible to check with your pharmacist if a patient purchasing a H2-antagonist says they are taking any other medication.

Other products

Domperidone is available as an OTC product for the feeling of nausea, fullness and bloating sometimes associated with indigestion. It is a dopamine antagonist (also sometimes referred to as a prokinetic) that works by stimulating the muscles in the upper GI tract, ie the oesophagus, to move food down into the stomach, the stomach to empty and the small intestine to move food along. The recommended dosing is one tablet three times a day and at night before food if required, and the product may only be sold to customers over the age of 16.   Side effects are rare, but domperidone can interact with other drugs, including strong painkillers that contain codeine, so anyone asking for the product should be referred to the pharmacist.

Back to your customer...

You start by asking if the woman's symptoms have been brought on by anything in particular, as certain foods (chocolate, coffee, alcohol, fatty or spicy foods) and medicines (see ‘When to refer' box) can irritate the stomach.   She says that she hasn't noticed anything, but wonders if it is due to the fact that she is 20 weeks pregnant. You explain that the growing baby is probably causing the discomfort, as the GI tract becomes more squashed as the baby increases in size. You can reassure her that heartburn is very common during pregnancy (as it is in overweight people for the same reason). You recommend a simple antacid that contains an alginate, first checking the sodium content to avoid putting the woman's blood pressure up (which can be dangerous during pregnancy). The woman opts for the liquid over the tablet version of the preparation, as she wants rapid relief when her symptoms come on at bedtime. You recommend a few more measures that may help, such as adding an extra pillow so her head is slightly raised at night, minimising stress, and ensuring she exercises regularly to keep the GI tract moving efficiently. You also advise the woman to avoid triggers such as rushed meals, fatty or spicy food, caffeine and smoking.

Key points

Indigestion symptoms result from stomach acid attacking the sensitive lining of the upper GI tract Indigestion remedies fall into three main categories – antacids, proton pump inhibitors and H2-antagonists Antacids offer rapid relief of symptoms, but will not prevent recurrence. PPIs and H2-antagonists are good for preventing the onset or worsening of symptoms, but will not quickly ease existing symptoms Simple lifestyle measures can reduce the chance of getting indigestion as well as help relieve symptoms.

When to refer

OTC indigestion remedies are not suitable for all, and the following patients should always be referred to the pharmacist or GP: Children Individuals complaining of chest pain that is severe or radiates down the arm or into the back Anyone who reports breathing or swallowing difficulties, or chest tightness Patients who are vomiting or have seen blood in their stools Middle-aged customers who say that their symptoms have come on suddenly or who have unintentionally lost a lot of weight Individuals who are taking any other medication, but particularly NSAIDs such as aspirin or ibuprofen, or nitrates for angina Anyone buying OTC indigestion remedies frequently or in large quantities Pregnant women complaining of very severe indigestion symptoms Patients complaining of severe or persistent pain.


Are you familiar with your pharmacy's indigestion product range? Work out which are antacids, PPIs and H2-antagonists Work out which antacids contain alginates Looking at the packaging for the indigestion remedies you stock, what would you recommend to the following customers?

  • a middle-aged man worrying that the rich food and alcohol at a work dinner event will upset his stomach

  • a woman with indigestion who says that she feel bloated and a bit constipated

  • a man who has been taking a PPI for a week but says his symptoms are no better

Talk through your answers with your colleagues and pharmacist.


C+D Guide to OTC Medicines contains a chapter on indigestion, including information on products and a recommendation flowchart.  

NHS Choices NHS Choices  

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