Calcium Carbonate

1 medicine

Calcium carbonate is an antacid and calcium supplement that neutralises stomach acid and supports bone health. Excessive intake, especially with dairy or other alkali, can cause milk-alkali syndrome, and it reduces absorption of many other drugs.

Calcium Carbonate Tablets

Calcium carbonate

500mg

Calcium Carbonate Tablets is a bone support medication containing Calcium carbonate, available as 500mg tablets.

from $0.72 / tablet View

Key facts

  • Calcium carbonate neutralises stomach acid quickly and also supplies elemental calcium for people who need more in their diet.
  • It is taken as chewable or regular tablets, or as a liquid, usually with or after food for indigestion, or with meals for calcium supplementation.
  • Taking large amounts, especially alongside large quantities of dairy or other alkaline substances, can cause milk-alkali syndrome: raised blood calcium, kidney injury, and a shift in blood pH.
  • It reduces the absorption of many other medicines, so take other drugs at least 2 hours apart from calcium carbonate where possible.

What calcium carbonate treats

Calcium carbonate relieves indigestion, heartburn, and acid reflux by neutralising excess stomach acid. As a supplement, it treats or prevents calcium deficiency and supports bone health, often alongside vitamin D, in people at risk of osteoporosis or with inadequate dietary calcium.

How calcium carbonate works

As an antacid, calcium carbonate reacts directly with hydrochloric acid in the stomach, neutralising it and raising the stomach's pH, which eases the burning discomfort of acid reflux and indigestion. As a supplement, it provides elemental calcium that the gut absorbs and the body uses to build and maintain bone and to support nerve, muscle, and clotting function.

Before you take it

  • Do not take calcium carbonate if you have high blood calcium, a history of calcium-containing kidney stones without medical guidance, or severe kidney disease, unless your prescriber advises otherwise.
  • Tell your prescriber about thyroid medicine, certain antibiotics (tetracyclines and quinolones), iron supplements, and bisphosphonates, since calcium carbonate can block their absorption if taken together.
  • Separate other medicines from calcium carbonate by at least 2 hours, longer where the interacting drug's information advises it.
  • Avoid combining high-dose calcium supplements with large amounts of dairy products or other alkaline antacids over a long period.

Side effects

Common effects include constipation, bloating, gas, and a chalky taste.

Stop and seek urgent medical care for any of these:

  • Nausea, vomiting, confusion, or unusual tiredness, which can signal high blood calcium.
  • Reduced urination or signs of kidney problems.
  • Severe constipation or abdominal pain.
  • Muscle weakness or an irregular heartbeat.

Safety essentials

  • Avoid taking large amounts of calcium carbonate together with dairy products or other alkaline substances over time. This combination can cause milk-alkali syndrome, a serious condition of high blood calcium, kidney injury, and disturbed blood chemistry.
  • Because calcium carbonate binds to many drugs in the gut, separate it from other medicines, especially thyroid hormone, certain antibiotics, iron, and bisphosphonates, by at least 2 hours.
  • Do not exceed the recommended daily calcium intake from supplements and food combined without medical advice, particularly if you take other calcium or vitamin D products.
  • People with kidney disease should use calcium carbonate only under medical supervision, since impaired kidneys clear excess calcium less effectively.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.