Calcium carbonate (Rennie orange)
How does it work?
Rennie orange flavour tablets contain the active ingredient calcium carbonate, which is a type of medicine called an antacid.
Antacids are used to reduce the acidity of the stomach's juices. Stomach acid is produced in the stomach as a normal part of the digestive process. However, too much stomach acid can cause symptoms such as heartburn and indigestion. It can also irritate an inflamed stomach lining or an ulcer in the stomach or intestine (peptic ulcer).
Calcium carbonate works by binding to and neutralising excess acid produced by the stomach. This helps to relieve the pain and discomfort of indigestion, heartburn and other symptoms related to excess stomach acid.
Antacids work as soon as they reach the stomach.
What is it used for?
- Relieving indigestion, heartburn and flatulence (excess gas). This includes indigestion due to over-indulgence in food or drink, heartburn in pregnancy and nervous indigestion.
- Relieving an upset stomach characterised by stomach pain and bloating, nausea and excess gas (dyspepsia).
How do I take it?
- Adults and adolescents aged over 12 years should take two tablets, preferably an hour after meals and before bedtime, as needed to relieve symptoms. Extra doses of two tablets can be taken if needed, but do not take more than 16 tablets in a day.
- The tablets can be sucked or chewed.
- Do not exceed the recommended dose.
- Indigestion and heartburn can sometimes be symptoms of more serious conditions such as stomach ulcers or stomach cancer. For this reason, you should consult your doctor before taking this medicine if any of the following apply to you:
- you are aged 55 years or older and have new or recently changed indigestion or heartburn symptoms
- you have needed to use heartburn or indigestion remedies continuously for two or more weeks to control your symptoms
- you have difficulty or pain swallowing
- you have persistent stomach pain or unintended weight loss associated with indigestion
- you have blood in your stools or black, tarry stools
- you have persistent vomiting or vomiting blood
- you have had a peptic ulcer in the past
- you are taking a non-steroidal anti-inflammatory drug (NSAID), eg aspirin, ibuprofen, diclofenac, indometacin, naproxen, azapropazone, piroxicam, ketoprofen.
- If your symptoms persist or get worse despite taking this medicine you should consult your doctor or pharmacist.
Use with caution in
- People with decreased kidney function.
- People with a history of kidney stones.
Not to be used in
- Children under 12 years of age.
- People with severely decreased kidney function.
- People with very high levels of calcium in their urine (hypercalciuria) or kidney stones containing calcium.
- People with high levels of calcium in their blood (hypercalcaemia), for example as a result of bone marrow cancer, cancer that has spread to the bones or overactivity of the parathyroid glands (hyperparathyroidism).
- People with low levels of phosphate in their blood (hypophosphataemia).
- People with rare hereditary problems of fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency.
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- There are no known harmful effects if this medicine is used by pregnant or breastfeeding mothers. It may be used to relieve indigestion and heartburn associated with pregnancy or when breastfeeding. However, do not take more than the recommended dose.
- It is best to avoid consuming excessive quantities of milk and other dairy products at the same time as taking this medicine, just to make sure that the level of calcium in your blood doesn't rise too high.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
- Gut disturbances such as constipation or diarrhoea.
- If used regularly for long periods of time there may be an increase in the level of calcium in the blood (hypercalcaemia).
- If used regularly for long periods of time there may also be a rebound increase in the amount of stomach acid produced after you stop taking the tablets.
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
Antacids such as calcium carbonate can reduce the absorption of many other medicines from the gut, which may make the other medicines less effective. If you are taking any other medicines, get advice from your pharmacist before taking this antacid. Antacids should preferably not be taken at the same time of day as any other medicines. In general, any interactions can be avoided if you do not take this medicine in the about two hours before and after taking any other medicine.
This is particularly important for the following medicines:
- bisphosphonates, eg alendronate, etidronate
- enteric-coated tablets
- iron preparations, eg ferrous sulphate, ferrous fumarate, ferrous gluconate
- quinolone-type antibiotics eg ciprofloxacin, norfloxacin, nalidixic acid, moxifloxacin (If you are prescribed a course of one of these antibiotics it is recommended that you take the antibiotic at least two hours before or four to six hours after taking this medicine)
- sodium fluoride
- strontium ranelate
- tetracycline-type antibiotics, eg doxycycline, minocycline, tetracycline (If you are prescribed a course of one of these antibiotics it is recommended that you take the antibiotic at least two hours before or four to six hours after taking this medicine)
- ulipristal (you should not take the morning-after pill EllaOne if you are regularly taking this antacid)
Other medicines containing the same active ingredient
- Boots indigestion relief tablets.
- Setlers antacid.
- Tums assorted fruit antacid.