Is Calcium (Calcium Carbonate) Safe with Omeprazole?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Replace calcium carbonate with calcium citrate in all patients on chronic omeprazole therapy. Calcium citrate is absorbed independently of gastric acid. Dose calcium citrate in divided doses (500 mg per dose) for optimal absorption and take with adequate vitamin D.
Why this interaction occurs
Omeprazole raises intragastric pH to 4–6, creating an environment where calcium carbonate remains largely undissolved and unabsorbed. Studies demonstrate up to a 40% reduction in calcium absorption from carbonate salts under acid suppression. This interaction contributes to negative calcium balance, secondary hyperparathyroidism, and elevated fracture risk with prolonged use.
Evidence
Evidence level: strong.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 365,179 reports mentioning Omeprazole. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Omeprazole + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
All Calcium (Calcium Carbonate) interactions → · All Omeprazole interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.