An H2 blocker that reduces stomach acid
Ranitidine
An acid-reducing medicine for reflux and ulcers that has largely been withdrawn in the UK over a contaminant concern.
What is Ranitidine?
Ranitidine is an H2 blocker, a medicine that reduces the amount of acid the stomach makes, used for heartburn, acid reflux and stomach or duodenal ulcers. It is generally well tolerated. However, UK and EU supplies were withdrawn after concerns that some batches contained a contaminant called NDMA, so ranitidine is now largely unavailable and other acid-reducing medicines are usually used instead. Anyone who previously took it should speak to their pharmacist or doctor about an alternative.
Education and reference only. This is a plain-language guide to Ranitidine — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Ranitidine is a medicine known as an H2 blocker, which reduces how much acid the stomach produces. It was widely used to treat conditions linked to stomach acid, including heartburn and acid reflux, inflammation of the gullet, and stomach and duodenal ulcers. It is taken by mouth. Although it was a familiar and well-tolerated medicine for many years, supplies in the UK and the EU were withdrawn after concerns that some batches contained a probable cancer-causing impurity called NDMA. As a result it is now largely unavailable, and other acid-reducing medicines are generally used in its place.
How it works
Ranitidine works by blocking histamine receptors on the acid-producing cells in the stomach lining. Histamine is one of the signals that tells these cells to make acid, so by blocking its effect ranitidine reduces the amount of acid produced. With less acid, symptoms such as heartburn and reflux ease, and ulcers and inflamed areas are given a chance to heal. It is a different type of acid reducer from the proton pump inhibitors, working in a milder, separate way, which is why it was often used for acid-related symptoms before the safety concerns arose.
Company & origin
Originated / developed by: Various manufacturers.
A long-established acid-reducing medicine once widely used in the UK for reflux and ulcers; UK and EU supplies were withdrawn over a contaminant concern, so it is now largely unavailable.
What it treats
Conditions Ranitidine is used for
Practical use
How to take Ranitidine
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Because UK and EU supplies were withdrawn, ranitidine is now largely unavailable; speak to your pharmacist or doctor about an alternative.
- If you previously took it for reflux or an ulcer, ask about a suitable replacement acid-reducing medicine rather than going without.
- Do not obtain ranitidine from unregulated or overseas sources because of the contaminant concern.
- Take any replacement medicine exactly as advised, and mention any other medicines you take.
- Tell your clinician if your symptoms are not controlled so your treatment can be reviewed.
Weighing it up
Advantages & disadvantages of Ranitidine
Advantages
- Reduces stomach acid and was generally well tolerated when it was in use.
- Eased heartburn and reflux and helped ulcers and inflamed areas heal.
- A different type of acid reducer from proton pump inhibitors, offering another option at the time.
Disadvantages
- UK and EU supplies were withdrawn over a contaminant (NDMA) concern, so it is now largely unavailable.
- It is no longer a practical choice, and an alternative acid reducer is usually needed.
- It should not be sourced from unregulated suppliers.
Practical use
Good to know
The most important thing to know about ranitidine today is the safety background: UK and EU supplies were withdrawn after some batches were found to contain a contaminant called NDMA, which is a probable cancer-causing substance, so ranitidine is now largely unavailable here. This was a precaution about the impurity rather than a problem with how the medicine itself worked, as ranitidine was generally well tolerated. If you used to take it, the practical message is to speak to your pharmacist or doctor, who can suggest a suitable alternative acid-reducing medicine. You should not try to source ranitidine from unregulated sources. Other H2 blockers and proton pump inhibitors are widely available and are now used instead for reflux and ulcers.
Who should not take it / use with caution
- It is now largely unavailable in the UK and EU and should not be obtained from unregulated sources.
- People who had a serious allergic reaction to ranitidine should not take it.
- Anyone needing acid treatment should ask their clinician about an alternative rather than using withdrawn supplies.
- Its use, where any remains, would be decided with care in pregnancy and breastfeeding by a clinician.
Monitoring
- Reviewing symptoms and switching to a suitable alternative acid reducer where needed.
- Checking that reflux or ulcer symptoms are controlled on the replacement medicine.
- Following official guidance on the withdrawal of ranitidine supplies.
Side effects
- When it was in use it was generally well tolerated, with side effects being uncommon.
- Occasionally headache, dizziness or stomach upset such as constipation or diarrhoea.
- Rarely, allergic reactions or changes in blood tests.
- The main present-day concern is the NDMA contaminant found in some batches, which led to its withdrawal.
Key interactions
- By reducing stomach acid it could affect how some medicines that need acid are absorbed.
- It had fewer interactions than some other acid reducers, but a full medicines list is still important for any alternative.
- Discuss with your pharmacist how any replacement acid reducer fits with your other medicines.
Available as: Was available as tablets and a liquid taken by mouth; supplies are now largely withdrawn.
Answers
Ranitidine: frequently asked questions
What is ranitidine used for?
It is an H2 blocker that reduces stomach acid, used for heartburn, acid reflux and stomach or duodenal ulcers, though it is now largely unavailable.
Why was ranitidine withdrawn?
UK and EU supplies were withdrawn after some batches were found to contain a contaminant called NDMA, a probable cancer-causing substance; it was a precaution about the impurity.
Is ranitidine safe to take?
Because of the contaminant concern it is now largely unavailable and should not be sourced from unregulated suppliers; speak to your pharmacist or doctor about an alternative.
What can I take instead?
Other H2 blockers and proton pump inhibitors are widely available and are now used instead; your pharmacist or doctor can recommend a suitable one.
Was it otherwise a safe medicine?
Ranitidine was generally well tolerated in use, with uncommon side effects; the reason for its withdrawal was the NDMA impurity, not how the medicine itself worked.
The wider class
About H2-receptor antagonist (acid reducer)
Ranitidine belongs to the h2-receptor antagonist (acid reducer) class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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