Is Calcium (Calcium Carbonate) Safe with Lansoprazole?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Switch to calcium citrate supplementation, which does not require gastric acid for dissolution and absorption. If calcium carbonate must be used, take it with meals when some acid may be present. Monitor bone density (DEXA scan) with long-term PPI use.
Why this interaction occurs
Calcium carbonate requires an acidic gastric environment (pH < 4) to dissolve and ionize into absorbable Ca²⁺. Lansoprazole significantly raises gastric pH, reducing calcium carbonate solubility by up to 40%. Long-term PPI use is associated with increased risk of hip, wrist, and spine fractures, partly through this mechanism.
Evidence
Evidence level: strong.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 110,199 reports mentioning Lansoprazole. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Lansoprazole + 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 Lansoprazole interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.