Drug interactions
Cimetidine + Iron
Severity: Moderate
Cimetidine 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
Cimetidine can lower oral iron absorption by reducing gastric acid. Prolonged use may reduce the response to iron therapy.
What this interaction means in plain words
Cimetidine 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.
Cimetidine belongs to Gastrointestinal Tract; Iron belongs to Gastrointestinal Tract.
Why it happens
Acid suppression raises gastric pH and decreases solubility and reduction of ferric iron to the absorbable ferrous form.
What to do
Monitor hemoglobin and ferritin in patients on long-term acid suppression and consider a higher iron dose or intravenous iron if response is inadequate. Giving iron with vitamin C may help.
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 carbonate + Iron Moderate
- Calcium citrate + Iron Moderate
Other interactions of Cimetidine
- Cimetidine + Dofetilide Contraindicated
- Cimetidine + Fezolinetant Contraindicated
- Alfentanil + Cimetidine Major
- Atazanavir + Cimetidine Major
- Carmustine + Cimetidine Major
- Cimetidine + Citalopram Major
Frequently asked questions
Can I take Cimetidine with Iron?
MediHelp rates the interaction as moderate. Cimetidine 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. Cimetidine can lower oral iron absorption by reducing gastric acid. Prolonged use may reduce the response to iron therapy.
How serious is the interaction between Cimetidine 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: Monitor hemoglobin and ferritin in patients on long-term acid suppression and consider a higher iron dose or intravenous iron if response is inadequate. Giving iron with vitamin C may help.
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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