Ranitidine Effect on Calcium Absorption

Millions of people take calcium supplements for conditions such as hypocalcemia or osteoporosis, or to maintain general bone health. Unfortunately, some calcium supplements require an acidic environment for proper dissolution. This can cause a problem in patients who use medications such as ranitidine that can lower the production of gastric acid.

Calcium supplements are available over the counter
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Ranitidine is a medication used to treat heartburn symptoms associated with acid reflux. Available over the counter or by prescription, ranitidine blocks H2 receptors in the gastric lining. Under normal circumstances, H2 receptors stimulate the secretion of stomach acid following activation by histamine. As acid production is lowered, patients may feel an improvement in heartburn symptoms.

Calcium Supplements

Many types of calcium supplements are available. Although some patients have health condition such as osteoporosis, many people take calcium to supplement insufficient dietary intake. The two most popular forms of calcium supplements are calcium carbonate and calcium citrate.

Ranitidine and Calcium Carbonate

Calcium carbonate is the most popular form of calcium on the market because of its low cost and high elemental calcium content. Unfortunately, calcium carbonate does require an acidic environment to properly dissolve. Calcium carbonate must be dissolved before it can be absorbed into the body. Since food stimulates the production of stomach acid, calcium carbonate is often taken with meals. However, patients who take acid reducing medications such as ranitidine may have impaired absorption with calcium carbonate.

Calcium Citrate

Although not as popular, calcium citrate does offer some advantages over calcium carbonate. Since calcium citrate absorption is not significantly affected by stomach acidity, it can be taken with or without meals. In addition, calcium citrate may be a good supplement option for patients who take acid reducing medications such as ranitidine for acid reflux. However, calcium citrate contains less elemental calcium per weight basis -- 21 percent, compared with calcium carbonate at 40 percent.


In most cases, calcium carbonate is a good choice for supplementation since it contains 40 percent elemental calcium and is relatively inexpensive. However, patients who use acid reducing medications such as ranitidine may want to consider calcium citrate as an alternative. Both calcium carbonate and calcium citrate are available over the counter without a prescription. Patients should talk to their physician about which calcium supplement is best for them.

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