Calnat

Calnat 500mg Chewable Tablets are to be chewed as a supplemental source of calcium in the correction of dietary deficiencies or when normal requirements are high.

Calnat 500mg Chewable Tablets may be used as an adjunct to conventional therapy in the prevention and treatment of osteoporosis. They may be used as a phosphate binding agent in the management of renal failure in patients on renal dialysis.

Posology

Adults:

Special patient populations

Elderly patients:

Dosage as for adults.

Paediatric patients:

Impaired renal function:

In patients with severe renal failure having a creatinine clearance of less than 30 ml/minute, dosage adjustments may be necessary dependent on serum calcium levels.

Impaired hepatic function:

No dose adjustment is required.

Method of administration

Oral.

Tablets may be chewed or sucked.

For phosphate binding, the tablets should be taken just before, during or just after each meal in order to bind phosphate in the food.

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- Diseases and/or conditions resulting in hypercalcaemia and/or hypercalciuria, for example in hyperparathyroidism, vitamin D overdosage, decalcifying tumours such as plasmacytoma and skeletal metastases, in severe renal failure untreated by renal dialysis and in osteoporosis due to immobilisation.

- Renal calculi (nephrolithiasis)

In renal insufficiency the tablets should be given only under controlled conditions for hyperphosphataemia. Caution should be exercised in patients with a history of renal calculi.

During long-term treatment, serum calcium levels should be followed and renal function should be monitored through measurements of serum creatinine. Monitoring is especially important in patients on concomitant treatment with cardiac glycosides or diuretics (see 4.5), in patients with a high tendency to calculus formation, in cases of hypercalcaemia, or signs of impaired renal function.

Calcium carbonate should be used with caution in patients with hypercalcaemia or signs of impaired renal function and the effect on calcium and phosphate levels should be monitored. The risk of soft tissue calcification should be taken into account.

During high dose therapy and especially during concomitant treatment with vitamin D and/or medications or nutrients (such as milk) containing calcium, there is a risk of hypercalcaemia and milk-alkali syndrome (hypercalcaemia, alkalosis and renal impairment) with subsequent kidney function impairment. In these patients, serum calcium levels should be followed and renal function should be monitored.

Calnat 500 mg Chewable Tablets contain isomalt (E953). Patients with rare hereditary problems of fructose intolerance should not take this medicine.

Calcium carbonate has no known influence on ability to drive and use machines.

Adverse reactions are listed below, by system organ class and frequency. Frequencies are defined as: uncommon (>1/1,000 to <1/100); rare (>1/10,000 to <1/1,000) or very rare (≤1/10,000)

Metabolism and nutrition disorders

Uncommon: Hypercalcaemia and hypercalciuria.

Very rare: Milk-alkali syndrome (frequent urge to urinate; continuing headache; continuing loss of appetite; nausea or vomiting; unusual tiredness or weakness; hypercalcaemia, alkalosis and renal impairment). Seen usually only in overdose (see 4.9).

Gastrointestinal disorders

Rare: Constipation, dyspepsia, flatulence, nausea, abdominal pain and diarrhoea.

Skin and subcutaneous disorders

Very rare: Pruritus, rash and urticaria.

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: www.mhra.gov.uk/yellowcard.

Overdose can lead to hypercalcaemia. Symptoms of hypercalcaemia may include anorexia, thirst, nausea, vomiting, constipation, abdominal pain, muscle weakness, fatigue, mental disturbances, polydipsia, polyuria, bone pain, nephrocalcinosis, nephrolithiasis and in severe cases, cardiac arrhythmias. Extreme hypercalcaemia may result in coma and death. Persistently high calcium levels may lead to irreversible renal damage and soft tissue calcification.

Milk-alkali syndrome may still occur in patients who ingest large amounts of calcium and absorbable alkali. It is not uncommon as a cause of hypercalcaemia requiring hospitalisation. The syndrome has also been reported in a patient taking recommended doses of antacids containing calcium carbonate for chronic epigastric discomfort, and in a pregnant woman taking high, but not grossly excessive, doses of calcium (about 3 g of elemental calcium daily). Metastatic calcification can develop.

Treatment of hypercalcaemia: The treatment with calcium must be discontinued. Treatment with thiazide diuretics, lithium, vitamin A, vitamin D and cardiac glycosides must also be discontinued. Treatment: rehydration, and, according to severity of hypercalcaemia, isolated or combined treatment with loop diuretics, bisphosphonates, calcitonin and corticosteroids should be considered. Serum electrolytes, renal function and diuresis must be monitored. In severe cases, ECG and CVP should be followed.

Pharmacotherapeutic group: Calcium

ATC-code: A12A A04

An adequate intake of calcium is of importance during growth, pregnancy and breastfeeding.

Absorption: The amount of calcium absorbed through the gastrointestinal tract is approximately 30% of the swallowed dose.

Distribution and biotransformation: 99% of the calcium in the body is concentrated in the hard structure of bones and teeth. The remaining 1% is present in the intra- and extracellular fluids. About 50% of the total blood-calcium content is in the physiologically active ionised form with approximately 10% being complexed to citrate, phosphate or other anions, the remaining 40% being bound to proteins, principally albumin.

Excretion and elimination: Calcium is eliminated through faeces, urine and sweat. Renal excretion depends on glomerular filtration and calcium tubular reabsorption.

Not applicable.

Dispose of the medication in accordance with local regulations for medical waste.