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.
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.
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.
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.
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.
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.
Store in a cool, dry place away from the reach of children.
Medicines must not be used past the expiry date.