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Terms Of Use


Brand Name(s) : Tagamet, Peptimax
Side Effects


Cimetidine should be used with caution in: patients with kidney or liver problems, those who have or have had stomach ulcers, particularly if they are taking a non-steroidal anti-inflammatory drug (NSAID), women who are pregnant or who are breastfeeding, and care should be taken in those whose symptoms change and who are middle-aged or older as this drug can mask the symptoms of gastric cancer.

It should not be used in: people allergic to cimetidine or to any other ingredient in the medicine

Also see list of precautions and interactions.


Store below 25°C


What is it used for?

  • Cimetidine is used to treat a number of problems.
  • It is a member of a class of stomach acid anti-secretory drugs, sometimes known as histamine H2-receptor antagonists.
  • It is used to reduce the production of stomach acid.
  • In general this drug is used to reduce the production of stomach acid and symptoms associated with excess acid production such as indigestion or heartburn, such as in gastro-oesophageal reflux disease (GORD), but is also used to help heal ulcers in the stomach or in the upper intestine (duodenum).
  • Benefits of being on this drug include the prevention of excess acid production by the stomach which can lead to the relief of GORD symptoms and may allow healing of ulcers or erosions.

Listed below are the typical uses of cimetidine.

  • Treatment of gastro-oesophageal reflux disease (sometimes called GORD, dyspepsia or heartburn) and relief of associated symptoms such as dyspepsia (indigestion, including pain, bloating or nausea), heartburn and epigastric pain (pain in the chest behind the breast bone)
  • Treatment of duodenal (upper intestinal) and gastric (stomach) ulcers and erosions, including ulcers associated with non-steroidal anti-inflammatory (NSAID) drug use
  • Prevention of stomach acid aspiration (inhalation of stomach acid into the airways), which may happen during a surgical operation or in pregnant women during child birth
  • To increase absorption of nutrients, chemicals and fluid from the gut in patients with a condition known as short bowel syndrome
  • To reduce the degradation of enzyme supplements given to patients with pancreatic insufficiency (a condition in which pancreas fails to naturally produce enough enzyme to digest food)
  • Controlling symptoms of Zollinger–Ellison syndrome (a disorder in which excess stomach acid is produced).

On occasion your doctor may prescribe this medicine to treat a condition not on the above list.


How often do I take it?

  • Take this medication orally, every day, with meals and before bedtime. Tablets should be taken whole with a glass of water.
  • Use this medication regularly in order to get the most benefit from it.
  • Remember to use it at the same time each day - unless specifically told otherwise by your doctor.
  • It may take some time before the full benefit of this drug takes effect.
  • Certain medical conditions may require different dosage instructions as directed by your doctor.

What dose?

  • Dosage is based on your age, gender, medical condition, response to therapy, and use of certain interacting medicines.

Do I need to avoid anything?

  • This medicine is unlikely to affect driving ability or the ability to operate machinery. Consult your doctor or pharmacist for more details.

When can I stop?

  • It is important to continue taking this medication even if you feel well, unless your doctor tells you to stop.


Only the most common side effects have been listed. If any of these persist or you consider them severe then inform your doctor.

Tell your doctor immediately if you develop any of the following symptoms: liver disorder, indicated by stomach or gut tenderness, loss of appetite and jaundice (yellowing of the skin and eyes); depression, confusion or hallucinations; pancreatitis (symptoms of severe pain in the belly and back, feeling sick, vomiting and fever).

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching/swelling (especially of the face/tongue/throat), dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

The Yellow Card Scheme allows you to report suspected side effects from any type of medicine (which includes vaccines, herbals and over the counter medicines) that you are taking. It is run by the medicines safety watchdog called the Medicines and Healthcare products Regulatory agency (MHRA). Please report any suspected side effect on the Yellow Card Scheme website.


Before taking cimetidine, tell your doctor or pharmacist if you are allergic to it; or to other H2-receptor antagonists, or if you have any other allergies.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: kidney or liver problems, stomach ulcers (particularly if taking a non-steroidal anti-inflammatory drug [NSAID]), are a woman who is pregnant or is breastfeeding.

Before using this medication, tell your doctor or pharmacist your medical history, especially any of the following: any previous kidney or liver problems, previous stomach ulcers or stomach cancer.

Before having surgery, tell your doctor or dentist that you are taking this medication.

Does alcohol intake affect this drug?

  • Alcohol is not known to affect this drug.

Pregnancy and breastfeeding - please ensure you read the detailed information below


The safety of cimetidine has not been established during pregnancy. Ask your doctor or pharmacist if you have any doubts or questions about this.

It is sensible to limit use of medication during pregnancy whenever possible. However, your doctor may decide that the benefits outweigh the risks in individual circumstances and after a careful assessment of your specific health situation.

If you have any doubts or concerns you are advised to discuss the medicine with your doctor or pharmacist.


Cimetidine is not safe to take if you are breastfeeding.

It is sensible to limit use of medication during breastfeeding whenever possible. However, your doctor may decide that the benefits outweigh the risks in individual circumstances and after a careful assessment of your specific health situation.

If you have any doubts or concerns you are advised to discuss the medicine with your doctor or pharmacist.


Before using this medicine, tell your prescriber of all the medicines you are taking including prescription medicines and medicines you have bought over the counter without a prescription. Tell your prescriber if you are taking vitamins or complementary remedies such as herbal products, as these can also interact with medicines.

If you are taking more than one medicine, these may interact with each other. Your prescriber may decide to use medicines which interact with each other if the benefit outweighs the risks. In these cases, the dose of your medicines may need to be adjusted or you may be monitored more closely.

The following medicines may interact with cimetidine:

  • Anti-malarials (artemether/lumefantrine).
  • Anti-psychotics, used in conditions such as schizophrenia (sertindole)
  • Ergot alkaloids, used to treat migraine (ergotamine and methysergide)
  • Anti-arrhythmics, to control heartbeat rhythm problems (e.g. lidocaine, procainamide or propafenone)
  • Anti-epileptic agents, used to control fits (e.g. carbamazepine, phenytoin and valproate)
  • Antifungals (e.g. posaconazole)
  • Blood-thinning agents (e.g. warfarin or acenocoumarol)
  • Cytotoxic agents (e.g. epirubicin)
  • Bronchodilators, used for breathing difficulties (e.g. theophylline)
  • The immunosuppressant ciclosporin

This information does not contain all possible interactions. Therefore, tell your prescriber of all the products you are using before taking this medicine.

If you have a question or want to discuss anything about your medicine, speak to your local pharmacist.


Overdoses with cimetidine have been reported, but without any significant adverse effects.

If you think you, or someone you care for, might have accidentally taken more than the recommended dose of Cimetidine or intentional overdose is suspected, contact your local hospital, GP or if in England call 111. In Scotland call NHS 24. In Wales, call NHS Direct Wales. In the case of medical emergencies, always dial 999.


If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgement of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse events, nor should it be construed to indicate that use of a particular medicine is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any medicine, changing any diet, or discontinuing any course of treatment.

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