Drug interactions
Calcium carbonate + Ferrous sulfate
Severity: Moderate
Calcium carbonate and Ferrous sulfate: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Calcium carbonate reduces absorption of oral iron, partly by raising gastric pH and by competing for uptake. This can blunt the response to iron therapy.
What this interaction means in plain words
Calcium carbonate and Ferrous sulfate can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Calcium carbonate belongs to Gastrointestinal Tract; Ferrous sulfate belongs to Miscellaneous.
Why it happens
Higher gastric pH and calcium competition decrease non-heme iron solubility and absorption.
What to do
Separate ferrous sulfate and calcium carbonate by at least 2 hours. Monitor hemoglobin and ferritin.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Calcium carbonate
Other interactions of Ferrous sulfate
Frequently asked questions
Can I take Calcium carbonate with Ferrous sulfate?
MediHelp rates the interaction as moderate. Calcium carbonate and Ferrous sulfate can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Calcium carbonate reduces absorption of oral iron, partly by raising gastric pH and by competing for uptake. This can blunt the response to iron therapy.
How serious is the interaction between Calcium carbonate and Ferrous sulfate?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Separate ferrous sulfate and calcium carbonate by at least 2 hours. Monitor hemoglobin and ferritin.
What other medicines interact with Calcium carbonate?
MediHelp also lists interactions of Calcium carbonate with, for example, Acalabrutinib, Alendronate, Amlodipine-hydrochlorothiazide-valsartan. The full list is on the Calcium carbonate page.
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