Colecalciferol with calcium carbonate

How it works

Colecalciferol is converted in the liver and kidney to active calcitriol, which enhances intestinal calcium absorption, while calcium carbonate provides elemental calcium as substrate for bone mineralisation.

Prescribing in practice

• The most important safety point is the risk of hypercalcaemia and hypercalciuria, so it should be avoided in conditions predisposing to high calcium and used cautiously with other vitamin D or calcium products.
• Calcium carbonate reduces absorption of several drugs, notably oral bisphosphonates, levothyroxine, and certain antibiotics, which should be separated in time.
• Use with caution in renal impairment and in patients with a history of renal stones or sarcoidosis.

Monitoring

Monitor serum calcium (and renal function where relevant), particularly in those on high doses or with impaired renal function.

Counselling the patient

• Take any bisphosphonate, levothyroxine, or relevant antibiotic at a separate time from this supplement.
• Report symptoms such as nausea, thirst, constipation, or confusion that could indicate too much calcium.

Evidence & guidelines

Combined calcium and vitamin D supplementation is supported by NICE and NOGG guidance as adjunctive therapy alongside bone-protective treatment in osteoporosis.