Calcium carbonate

Calcium supplement
ALSO SOLD WITHOUT PRESCRIPTION

Calcium carbonate is a calcium supplement found in 3 medicines sold in India, such as Shelcal 500, Calcimax Forte, Shelcal XT. Below: what it is for, how it works, how to take it, side effects, interactions and pregnancy advice.

Also called: calcium

What it is used for

Provides calcium for bones and teeth; also acts as an antacid.

How it works

The most common calcium supplement (40 percent calcium), also an antacid. Supports bones and teeth with vitamin D.

How to take it

Take with meals for best absorption; no more than 500 to 600 mg of calcium at a time. Count calcium from milk, curd and paneer too.

Common side effects

  • Constipation
  • Wind
  • Bloating

Get medical help straight away if

  • Kidney stone pain
  • Confusion, thirst or vomiting (too much calcium)

Be careful

Can cause constipation; keep 2 to 4 hours apart from thyroid tablets and iron.

Other medicines and interactions

Reduces absorption of iron, levothyroxine, ciprofloxacin and other quinolones, tetracyclines and bisphosphonates; separate by 2 to 4 hours.

Pregnancy and breastfeeding

Calcium needs rise in pregnancy and breastfeeding; supplements are commonly prescribed.

Combination medicines that contain Calcium carbonate (3)

Calcimax ForteShelcal 500Shelcal XT

Common questions

What is Calcium carbonate used for?

Provides calcium for bones and teeth; also acts as an antacid.

How does Calcium carbonate work?

The most common calcium supplement (40 percent calcium), also an antacid. Supports bones and teeth with vitamin D.

How should I take Calcium carbonate?

Take with meals for best absorption; no more than 500 to 600 mg of calcium at a time. Count calcium from milk, curd and paneer too.

What are the side effects of Calcium carbonate?

Common: Constipation, wind, bloating. Get help straight away for: Kidney stone pain, confusion, thirst or vomiting (too much calcium).

Does Calcium carbonate interact with other medicines?

Reduces absorption of iron, levothyroxine, ciprofloxacin and other quinolones, tetracyclines and bisphosphonates; separate by 2 to 4 hours.

Is Calcium carbonate safe in pregnancy and breastfeeding?

Calcium needs rise in pregnancy and breastfeeding; supplements are commonly prescribed.

Does Calcium carbonate need a prescription in India?

It is usually sold without a prescription in India, but ask a pharmacist if you take other medicines or have a long-term illness.

Which brands contain Calcium carbonate?

Calcimax Forte, Shelcal 500, Shelcal XT.

Sources and further reading

NHS (UK National Health Service) and MedlinePlus (US National Library of Medicine) are free, reviewed medicine guides. Brand names and doses there may differ from India.

Last reviewed 31 October 2026. Written by Satya Babu from standard prescribing information.

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For information only, not medical advice. This page is a plain-language summary written from standard prescribing information and the public guides linked below. Brands sometimes change their formula, so always check the composition printed on the pack. Doses here are typical adult doses; yours may differ. Do not start, stop or change a medicine without your doctor or pharmacist, and keep all medicines away from children. In an emergency, call 112 (India) or your local emergency number.