Active substance(s): CALCIUM CARBONATE / MAGNESIUM CARBONATE HEAVY
NAME OF THE MEDICINAL PRODUCT
QUALITATIVE AND QUANTITATIVE COMPOSITION
Heavy Magnesium Carbonate
Also contains glucose and sucrose
For full list of excipients, see section 6.1
A square cream white tablet with rounded corners, bevelled edges and concave faces,
engraved ‘Rennie’ on both sides.
For the relief of indigestion, heartburn, nervous indigestion, hyperacidity,
flatulence, gastritis, upset stomach, dyspepsia, biliousness, overindulgence in
food and drink, indigestion during pregnancy.
Posology and method of administration
Tablets to be taken orally, sucked or chewed.
Adults and Children over 12 years:
Two tablets to be sucked or chewed as a single dose, preferably to be taken
one hour after meals and before going to bed but also in between in case of
heartburn or gastric pain. A maximum daily dose of 8 g calcium carbonate,
corresponding to 10 tablets a day, must not be exceeded.
Not recommended for children under 12 years of age.
As with all antacids, if symptoms persist despite 14 days of continuous
therapy, diagnostic measures are strongly recommended in order to rule out a
more serious disease.
Rennie should not be administered to patients with:
• Hypersensitivity to any of the ingredients of the product
• Hypercalcaemia and/or conditions resulting in hypercalcaemia
• Nephrolithiasis due to calculi containing calcium deposits
• Severe renal insufficiency
Special warnings and precautions for use
Prolonged use should be avoided.
The stated dose should not be exceeded. If, after 14 days of treatment,
symptoms persist or only partly disappear the patient should consult a
Caution should be exercised in patients with mild to moderate impairment of
renal function (see section 4.3 – contraindication in severe renal
insufficiency). If Rennie is used in such patients, plasma calcium, phosphate
and magnesium levels should be regularly monitored.
Long term uses at high doses can result in undesirable effects such as
hypercalcaemia, hypermagnesaemia and milk-alkali syndrome, especially in
patients with renal insufficiency.
Rennie should not be used in patients with hypercalciuria (see also section
4.3). Prolonged use increases the risk of formation of renal calculi.
This product should not be taken with large amounts of milk or dairy
Patients with rare hereditary problems of fructose intolerance, glucosegalactose malabsorption or sucrase-isomaltase insufficiency should not take
Interaction with other medicinal products and other forms of interaction
Changes in gastric acidity, such as that caused by the ingestion of antacids, can
affect the rate and degree to which some concurrently administered medicines
It has been shown that antacids which contain calcium or magnesium may
form complexes with certain substances e.g., antibiotics (such as
tetracyclines and quinolones), and cardiac glycosides (e.g. digoxin),
levothyroxine, and eltrombopag, resulting in decreased absorption. This
should be borne in mind when concomitant administration is considered.
Calcium salts reduce the absorption of fluorides and iron-containing
products, and calcium salts and magnesium salts can hinder the absorption
Thiazide diuretics reduce the urinary excretion of calcium. Due to an
increased risk of hypercalcaemia, serum calcium should be regularly
monitored during concomitant use of thiazide diuretics.
Therefore it is preferable to take the antacid separately from other drugs,
allowing at least 4 hours before or after taking eltrombopag and a 1-2 hour
interval for all other drugs.
Fertility, pregnancy and lactation
No increased risk of congenital defects has been observed after the use of this product
during pregnancy and it can be used during pregnancy and lactation if taken as
instructed but prolonged intake of high dosages should be avoided. Pregnant women
should limit the use of these products to the maximum recommended daily doses (see
During pregnancy and lactation, it has to be taken into account that the tablets provide
a substantial amount of calcium in addition to dietary calcium intake. For this reason,
pregnant women should strictly limit their use of tablets to the maximum
recommended daily dose and avoid concomitant, excessive intake of milk and dairy
products. This warning is to prevent calcium overload which might result in milkalkali syndrome.
Effects on ability to drive and use machines
No effects on ability to drive and use machines have been observed.
The listed adverse drug reactions are based on spontaneous reports, thus an
organisation according to CIOMS III categories of frequency is not possible.
Immune System Disorders:
Hypersensitivity reactions have very rarely been reported. Clinical
symptoms may include rash, urticaria, angioedema and anaphylaxis.
Metabolism and Nutrition Disorders:
Especially in patients with impaired renal function, prolonged use of high
doses can result in hypermagnesaemia or hypercalcaemia and alkalosis
which may give rise to gastric symptoms and muscular weakness (see
Nausea, vomiting, stomach discomfort and diarrhoea may occur.
Musculoskeletal and Connective Tissue Disorders:
Muscular weakness may occur.
Undesirable effects occurring in the context of milk-alkali syndrome (see
Ageusia may occur in the context of milk-alkali syndrome.
General Disorders and Administration Site Conditions:
Calcinosis and asthenia may occur in the context of milk-alkali syndrome.
Nervous System Disorders:
Headache may occur in the context of milk-alkali syndrome.
Renal and Urinary Disorders:
Azotemia may occur in the context of milk-alkali syndrome.
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal
product is important. It allows continued monitoring of the benefit/risk balance
of the medicinal product. Healthcare professionals are asked to report any
suspected adverse reactions via the Yellow Card Scheme at:
Especially in patients with impaired renal function, prolonged use of high doses
of calcium carbonate and magnesium carbonate can result in renal insufficiency,
hypermagnesaemia, hypercalcaemia and alkalosis which may give rise to
gastrointestinal symptoms (nausea, vomiting, constipation) and muscular
weakness. In these cases, the intake of the product should be stopped and
adequate fluid intake encouraged. In severe cases of overdosage (e.g. milk-alkali
syndrome), a health care professional must be consulted because other measures
of rehydration (e.g. infusions) might be necessary.
Pharmacotherapeutic Classification: Antacids
Calcium carbonate: A02AC01
Magnesium carbonate: A02AA01
Calcium and magnesium carbonates react with excess acid in the gastric juice to
produce soluble chlorides.
CaCO3 + 2HCl => CaCl2 + H2O + CO2
MgCO3 + 2HCl => MgCl2 + H2O + CO2
Calcium carbonate has a rapid and powerful neutralising action. This effect is
increased by the addition of magnesium carbonate which also has a strong
In healthy volunteers, a significant increase in the pH of stomach contents above
baseline pH was achieved between 1 and 6 minutes after dosing.
A small amount of calcium and magnesium may be absorbed, but in healthy subjects
is usually rapidly excreted by the kidney.
The soluble chlorides produced by the reaction of calcium and magnesium with
gastric acid react, in turn, with intestinal, biliary and pancreatic secretions to form
insoluble salts, which are excreted in the faeces.
Preclinical safety data
There is no information of relevance to the safety assessment in addition to what is
stated in other parts of the Summary of Product Characteristics.
List of excipients
Special precautions for storage
Store below 25 oC. Store in the original package.
Nature and contents of container
Tablets are packed in a hard tempered aluminium foil (20µm)/clear
thermoformable PVC (150µm) bubble pack, with six or twelve tablets per strip.
1, 2, 3, 4, 8, 10 or 12 strips are packed in a cardboard carton.
12 Tablet Pocket Pack – Tablets are packed in hard tempered aluminium foil
(20µm)/clear thermoformable PVC (250µm) bubble pack, with six tablets per
strip. Two strips are packed in a cardboard pocket pack.
12 tablet pack - tablets are roll wrapped in laminated foil consisting of
aluminium foil (7µm) externally, then polythene (12gsm), bleached kraft paper
(37gsm), and polythene (12gsm) internally.
3 roll wraps of 12 tablets may also be packed into a blister card to contain 36
Pack sizes: 6, 12, 24, 36, 48, 72, 96, 120, 144 tablets.
Special precautions for disposal
MARKETING AUTHORISATION HOLDER
Berkshire, RG14 1JA,
Trading as Bayer plc, Consumer Care Division
MARKETING AUTHORISATION NUMBER(S)
DATE OF FIRST AUTHORISATION/RENEWAL OF THE
1st July 2005
DATE OF REVISION OF THE TEXT
Source: Medicines and Healthcare Products Regulatory Agency
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