Drug interactions
Calcium + Ferrous fumarate
Severity: Moderate
Calcium and Ferrous fumarate: 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 supplements, particularly the carbonate salt, can lower absorption of oral ferrous fumarate. Iron repletion may be slower than expected.
What this interaction means in plain words
Calcium and Ferrous fumarate 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 belongs to Gastrointestinal Tract; Ferrous fumarate belongs to Miscellaneous.
Why it happens
Calcium competes with iron for intestinal absorption and carbonate raises gastric pH, decreasing iron solubility.
What to do
Take iron at least 2 hours apart from calcium. 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
- Calcium + Ceftriaxone Contraindicated
- Acalabrutinib + Calcium Moderate
- Alendronate + Calcium Moderate
- Atazanavir + Calcium Moderate
- Baloxavir marboxil + Calcium Moderate
- Bendroflumethiazide + Calcium Moderate
Other interactions of Ferrous fumarate
Frequently asked questions
Can I take Calcium with Ferrous fumarate?
MediHelp rates the interaction as moderate. Calcium and Ferrous fumarate 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 supplements, particularly the carbonate salt, can lower absorption of oral ferrous fumarate. Iron repletion may be slower than expected.
How serious is the interaction between Calcium and Ferrous fumarate?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Take iron at least 2 hours apart from calcium. Monitor hemoglobin and ferritin.
What other medicines interact with Calcium?
MediHelp also lists interactions of Calcium with, for example, Ceftriaxone, Acalabrutinib, Alendronate. The full list is on the Calcium page.
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