Calcium and Risedronate interaction
Calcium and Risedronate: the Risedronate prescribing label flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Risedronate (Risedronate Sodium) label · effective 2026-02-03
Calcium supplements, antacids, magnesium-based supplements or laxatives, and iron preparations interfere with the absorption of Risedronate sodium delayed-release and should not be taken together.
Calcium Supplements/Antacids When Risedronate sodium delayed-release was administered following breakfast, the co-administration of a tablet containing 600 mg of elemental calcium and 400 international units vitamin D reduced risedronate bioavailability by approximately 38% [ see Clinical Pharmacology (12.3) ] .
Instruct patients to take supplemental calcium and vitamin D if their dietary intake is inadequate.
Calcium supplements, antacids, proton pump inhibitors (PPIs), H 2 blockers, magnesium-based supplements or laxatives, and iron preparations interfere with the absorption of Risedronate sodium delayed-release ( 7.1 , 7.2 )
Curated guidance for Calcium
Calcium binds these drugs in the gut and can sharply cut how much is absorbed; separate the doses.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.