3. Cimetidine

Cimetidine

  • Cimetidine reduces the amount of acid produced in the stomach.
  • The most common side-effects are diarrhoea, headache, dizziness and tiredness. These effects are mild and do not last long.
Type of medicine H2-receptor antagonist
Used for Treatment of conditions caused by too much acid being produced in the stomach.
Also called Tagamet ®
Available as Tablets and oral liquid

Cimetidine is used to treat certain conditions caused by too much acid being produced in the stomach, such as stomach ulcers (gastric ulcers), ulcers of the upper part of the intestine (duodenal ulcers), acid reflux or heartburn (reflux oesophagitis) or indigestion. It can also be used to treat irritation and ulceration of the stomach caused by non-steroidal anti-inflammatory drugs (NSAIDs).

Acid is produced naturally in the stomach to help digest food. Excessive amounts of acid can irritate the stomach lining, causing inflammation, ulcers and other conditions. Cimetidine works by reducing the amount of acid produced in the stomach, relieving pain and helping to repair the damage.

Before taking cimetidine make sure your doctor or pharmacist knows:

  • If you are pregnant, trying for a baby or breast-feeding.
  • If you have liver or kidney problems.
  • If you have any of the following symptoms: bleeding, difficulty swallowing, being sick frequently, or unexplained weight loss.
  • If you have ever had an allergic reaction to this or any other medicine.
  • If you are taking any other medicines, including those available to buy without a prescription, herbal or complementary medicines.
  • Before beginning treatment, read the manufacturer's printed information leaflet.
  • Take this medicine exactly as directed by your doctor.
  • Try to take cimetidine at the same times each day to avoid missing any doses.
  • If you forget to take a dose, take it as soon as you remember unless it is nearly time for your next dose, in which case leave out the missed dose. Do not take two doses together to make up for a forgotten dose.
  • Your doctor may have prescribed you a course of treatment lasting a number of weeks. Keep your regular doctors appointments so your progress can be checked.
  • Do not smoke. Smoking increases the amount of acid produced by your stomach and may make your symptoms worse.
  • Try to avoid foods and drinks that may upset your stomach such as, alcohol, coffee, fatty or spicy food.
  • If you buy any medicines, especially painkillers, check with your pharmacist that they are safe for you to take alongside cimetidine.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Possible side-effects What can I do if I experience this
Diarrhoea Drink plenty of water to replace any lost fluids
Headache Ask your pharmacist to recommend a suitable painkiller. If the headache continues, speak with your doctor
Dizziness, skin rash, tiredness If troublesome, speak with your doctor

Important: If you experience any unexplained fever, sore throat, bruising or bleeding, speak with your doctor straight away.

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

  • 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 has taken an overdose of this medicine go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.
  • If you are having an operation or dental treatment tell the person carrying out the treatment which medicines you are taking.
  • This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
  • Never 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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Further reading & references

  • British National Formulary; 62nd Edition (Sep 2011) British Medical Association and Royal Pharmaceutical Society of Great Britain, London
  • Manufacturer's PIL, Cimetidine Oral Solution; Manufacturer's PIL, Cimetidine Oral Solution, Rosemont Pharmaceuticals Ltd, electronic Medicines Compendium. Dated September 2009.
  • Manufacturer's PIL, Cimetidine Tablets; Manufacturer's PIL, Cimetidine Tablets, Dexcel Pharma Ltd, electronic Medicines Compendium. Dated September 2008.
Original Author: Helen Allen Current Version:
Last Checked: 05/07/2011 Document ID: 3808  Version: 23 © EMIS

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

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