Cimetidine is a gastric medicine.
It is used to treat conditions 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 hypersecretory conditions such as Zollinger-Ellison syndrome (a condition in which a growth in the pancreas or duodenum or both secretes too much acid).
Cimetidine can also be used to relieve stomach irritation and ulceration caused by certain painkillers such as non-steroidal anti-inflammatory drugs (NSAIDs).
Cimetidine treats these conditions by reducing the amount of acid your stomach makes.
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.
You may need to take Cimetidine for some time before the full benefits can be felt.
Take Cimetidine with food or at bedtime.
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 liver or kidney disease.
Let your doctor know if you are pregnant or breastfeeding.
Do not take Cimetidine for more than 2 weeks unless directed by your doctor. Let your doctor know if your gastric problem seems to be getting worse or if there is no improvement even with Cimetidine.
Cimetidine may cause dizziness. If affected, do not drive or take part in any activity in which you need to be alert.
Other side effects include any of the following: diarrhoea (usually mild), headache, confusion, tiredness, muscle pain and rashes. These are usually temporary and should go away when Cimetidine is stopped.
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:
- blood-thinning medicines e.g. warfarin, clopidogrel
- medicines for high blood pressure or heart disease e.g. nifedipine, diltiazem, amiodarone
- medicines for sleep disorder or anxiety, or depression e.g. diazepam, chlordiazepoxide, amitriptyline
- medicines for fungal infections e.g. ketoconazole, itraconazole
- anticancer medicines e.g. carmustine, fluorouracil, epirubicin
- phenytoin (medicine for epilepsy or fits)
- theophylline (asthma medicine)
- metronidazole (antibiotic)
Do not take antacids together with Cimetidine. If you must take antacids, take them at least 1 hour before or 2 hours after you have taken Cimetidine.
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 medicine, supplements and medicines that you buy without a prescription.
It may be helpful to discuss your diet with your doctor or dietitian. A change in diet may help improve your symptoms. For example, spicy food tends to worsen reflux and should be avoided. Likewise, carbonated ("fizzy") drinks such as soft drinks should also be avoided.
You should also try to avoid lying down soon after eating as this will worsen the reflux symptoms.
Avoid alcohol and caffeine.
Store in a cool, dry place away from the reach of children.
Medicines must not be used past the expiry date.