Combinations requiring precautions for use:
Cardiac glycosides
Risk of serious dysrhythmia. Medical supervision and if necessary, monitoring electrocardiographic and calcaemia.
Bisphosphonates
Risk of decrease in the gastrointestinal absorption of bisphosphonates. It is advisable to take calcium salts apart from bisphosphonates (a minimum period of at least 2 hours)
Strontium
Reduction in strontium gastrointestinal absorption on concomitant administration of calcium-containing products. It is advisable to take calcium more than two hours apart from strontium-containing medications.
Tetracyclines orally
Possible reduction in the absorption of tetracycline. It is advisable to take calcium salts at least two hours apart from tetracyclines.
Rifampicin
Possible decrease in vitamin D concentrations. Vitamin D concentrations should be measured and supplementation provided if necessary.
Fluoroquinolones
Risk of reduction in the intestinal absorption of fluoroquinolones. It is advisable to take calcium more than two hours apart from fluoroquinolones.
Dolutegravir
Risk of reduction in the intestinal absorption of dolutegravir. It is advisable to take calcium at least 2 hours after or 6 hours before dolutegravir intake.
Ferrous salt
Risk of reduced gastrointestinal absorption of ferrous salt. It is advisable to allow a period of more than two hours between calcium and ferrous salt.
Zinc
Risk of reduced gastrointestinal absorption of zinc. It is advisable to allow a period of more than two hours between calcium and zinc.
Estramustine
Risk of reduction in the gastrointestinal absorption of estramustine. It is advisable to allow a period of more than two hours between calcium and estramustine.
Thyroid hormones
Risk of reduction in the gastrointestinal absorption of thyroid hormones. It is advisable to allow a period of more than two hours between calcium and thyroid hormones.
Enzyme-inducing antiepileptic drugs (AEDs) (carbamazepine, fosphenytoin, phenobarbital, phenytoin and primidone)
Possible decrease in vitamin D concentrations. Vitamin D concentrations should be measured and supplementation provided if necessary.
Roxadustat
The intake of divalent cation may decrease intestinal absorption and the efficacy of roxadustat when taken simultaneously.
Administration of calcium with roxadustat should be separated by more than 1 hour (if possible).
Combinations to be taken into account:
Orlistat
Treatment with orlistat may potentially reduce the absorption of Vitamin D3.
Thiazide diuretics
Risk of hypercalcemia due to a decrease in the urinary excretion of calcium. It is recommended that the calcium levels in plasma are monitored regularly.
Food
Possible interaction with food, for example foods containing oxalic acid (spinach, rhubarb, sorrel, cocoa, tea), phosphate (pork, ham, sausages, processed cheese, dessert cream, beverages containing cola, etc.) or phytic acid (wholemeal cereals, dry vegetables, oleaginous seeds, chocolate, etc.). These types of foods may reduce the absorption of calcium. It is therefore recommended that meals containing these foods be taken some time before or after ingestion of the product.