Cimetidine - oral

Patient Medicine Information
Why do I need this medicine?
Cimetidine is used to treat certain conditions that are caused by excessive acidity in your stomach, such as ulcers in the stomach or duodenum (upper portion of the small intestine), reflux disease (also known as "heartburn", in which food or acid from your stomach backs up into your mouth, leaving a sour or bitter taste), and Zollinger-Ellison syndrome (a condition in which a growth in the pancreas or duodenum or both secretes too much acid).

This medicine may also be used in the prevention of stomach ulcers associated with nonsteroidal anti-inflammatory drugs (medicines for pain and inflammation).

Cimetidine treats these conditions by reducing the amount of acid your stomach makes.

This medicine may be used to treat other conditions as decided by your doctor.
How do I take this medicine?
Take Cimetidine exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.

Take it together with food or immediately after a meal or during bedtime. Try to take it at the same time each day.

Cimetidine is available as a tablet or syrup.

If you are taking an oral syrup, shake the bottle well before you take it to ensure that the liquid is evenly mixed. Use the measuring spoon or cup provided to measure your dose.

The dose of this medicine will be decided by your doctor. Your doctor will advise you on the treatment timeframe depending on the type and severity of your condition.

Cimetidine must be taken regularly for it to be effective. Continue taking this medicine even when you feel better. Do not stop taking it unless instructed by the doctor.
What should I do if I have forgotten to take this medicine?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.

DO NOT double a dose under any circumstances.

If you often forget to take your medicine, let your doctor and pharmacist know.
What should I take note of while taking this medicine?
Inform your doctor if you have the following conditions:
  • weak immune system
  • history of stomach ulcer
  • kidney disease
  • liver disease
Let your doctor know if you are pregnant or breastfeeding.

Be sure to check with your doctor or pharmacist before giving this medicine to the elderly. Elderly people may be more sensitive to the side effects.

For as long as you are taking this medicine, you may need to have regular blood tests to check your body’s response to the medicine. Your doctor will advise you about how often you need to have blood tests.
What side effects could I experience?
Cimetidine may cause any of the following side effects: headache, dizziness, drowsiness, diarrhoea, tiredness, and rashes.

Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Can I take this with other medicines?
Inform your doctor and pharmacist if you are taking any of these medicines:
  • warfarin (blood-thinning medicine)
  • amitriptyline (medicine to treat depression)
  • medicines for irregular heartbeat e.g. procainamide, lidocaine
  • medicines for high blood pressure e.g. nifedipine, diltiazem, metoprolol
  • medicines for diabetes e.g. glipizide, metformin
  • phenytoin (medicine for epilepsy [fits or seizures])
  • theophylline (asthma medicine)
  • medicines for anxiety e.g. diazepam, chlordiazepoxide
  • certain antibiotics e.g. metronidazole
  • medicines to treat fungal infections e.g. ketoconazole, itraconazole
  • atazanavir (medicine for HIV infections)
  • medicines used in organ transplant or certain immune disorders e.g. ciclosporin, tacrolimus
  • medicines for cancer e.g. carmustine, fluorouracil, epirubicin
This list does not include all medicines that may interact with Cimetidine.

Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements and medicines that you buy without a prescription.
What special dietary instructions should I follow?
Avoid alcohol.
How should I store this medicine?
Store in a cool, dry place away from the reach of children.

Medicines must not be used past the expiry date.
This information is independently developed by MIMS based on cimetidine - oral and is provided for your reference only. It is not a replacement for and should only be used in conjunction with full consultation with a licensed healthcare professional, the information provided by your pharmacist and/or the manufacturer of the medication. It may not contain all the available information you require and cannot substitute professional medical care, nor does it take into account all individual circumstances. Although great effort has been made to ensure content accuracy, we shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2021 MIMS. All rights reserved. Powered by
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