Drug interactions
Calcium carbonate + Iron
Severity: Moderate
Calcium carbonate and Iron: 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, which can blunt the response to iron supplementation. The effect is most relevant when both are taken at the same time.
What this interaction means in plain words
Calcium carbonate and Iron 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; Iron belongs to Gastrointestinal Tract.
Why it happens
Increased gastric pH lowers iron solubility, and calcium competes with iron for intestinal absorption.
What to do
Separate oral iron from 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 Iron
- Acetohydroxamic acid + Iron Moderate
- Aluminum hydroxide + Iron Moderate
- Baloxavir marboxil + Iron Moderate
- Calcium acetate + Iron Moderate
- Calcium citrate + Iron Moderate
- Carbidopa + Iron Moderate
Other interactions of Calcium carbonate
Frequently asked questions
Can I take Calcium carbonate with Iron?
MediHelp rates the interaction as moderate. Calcium carbonate and Iron 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, which can blunt the response to iron supplementation. The effect is most relevant when both are taken at the same time.
How serious is the interaction between Calcium carbonate and Iron?
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 oral iron from calcium carbonate by at least 2 hours. Monitor hemoglobin and ferritin.
What other medicines interact with Iron?
MediHelp also lists interactions of Iron with, for example, Acetohydroxamic acid, Aluminum hydroxide, Baloxavir marboxil. The full list is on the Iron page.
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