Drug interactions
Cimetidine + Ferrous fumarate
Severity: Moderate
Cimetidine 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
Reduced gastric acid from cimetidine can impair absorption of oral ferrous salts, potentially blunting the response to iron therapy. The effect matters most with long-term acid suppression.
What this interaction means in plain words
Cimetidine 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.
Cimetidine belongs to Gastrointestinal Tract; Ferrous fumarate belongs to Miscellaneous.
Why it happens
Higher gastric pH reduces dissolution and conversion of iron to the absorbable ferrous form.
What to do
Monitor hemoglobin and ferritin response to oral iron. Consider taking iron with vitamin C or using intravenous iron if response is inadequate.
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 Cimetidine
- Cimetidine + Dofetilide Contraindicated
- Cimetidine + Fezolinetant Contraindicated
- Alfentanil + Cimetidine Major
- Atazanavir + Cimetidine Major
- Carmustine + Cimetidine Major
- Cimetidine + Citalopram Major
Other interactions of Ferrous fumarate
Frequently asked questions
Can I take Cimetidine with Ferrous fumarate?
MediHelp rates the interaction as moderate. Cimetidine 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. Reduced gastric acid from cimetidine can impair absorption of oral ferrous salts, potentially blunting the response to iron therapy. The effect matters most with long-term acid suppression.
How serious is the interaction between Cimetidine 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: Monitor hemoglobin and ferritin response to oral iron. Consider taking iron with vitamin C or using intravenous iron if response is inadequate.
What other medicines interact with Cimetidine?
MediHelp also lists interactions of Cimetidine with, for example, Dofetilide, Fezolinetant, Alfentanil. The full list is on the Cimetidine page.
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