Drug interactions
Calcium + Ferrous sulfate
Severity: Moderate
Calcium 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
Oral calcium salts reduce the absorption of non-heme iron when taken together, which can blunt the response to iron therapy. The effect is most relevant in iron deficiency or when both are taken regularly at the same time.
What this interaction means in plain words
Calcium 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 belongs to Gastrointestinal Tract; Ferrous sulfate belongs to Miscellaneous.
Why it happens
Calcium competes with iron for intestinal absorption, decreasing iron uptake.
What to do
Separate oral calcium and ferrous sulfate by at least 2 hours. Monitor hemoglobin and ferritin in patients treated for iron deficiency.
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 sulfate
Frequently asked questions
Can I take Calcium with Ferrous sulfate?
MediHelp rates the interaction as moderate. Calcium 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. Oral calcium salts reduce the absorption of non-heme iron when taken together, which can blunt the response to iron therapy. The effect is most relevant in iron deficiency or when both are taken regularly at the same time.
How serious is the interaction between Calcium 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 oral calcium and ferrous sulfate by at least 2 hours. Monitor hemoglobin and ferritin in patients treated for iron deficiency.
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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