Drug interactions
Carbonyl iron + Cimetidine
Severity: Moderate
Carbonyl iron and Cimetidine: 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 acidity can impair absorption of non-heme oral iron. Long-term cimetidine use may therefore blunt the response to iron supplementation.
What this interaction means in plain words
Carbonyl iron and Cimetidine 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.
Carbonyl iron belongs to Miscellaneous; Cimetidine belongs to Gastrointestinal Tract.
Why it happens
Cimetidine raises gastric pH, decreasing dissolution and absorption of oral iron salts.
What to do
Monitor hemoglobin and ferritin during prolonged co-therapy. Give iron with vitamin C or consider intravenous iron if response is poor.
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 Carbonyl iron
- Aluminum hydroxide + Carbonyl iron Moderate
- Baloxavir marboxil + Carbonyl iron Moderate
- Calcium acetate + Carbonyl iron Moderate
- Calcium carbonate + Carbonyl iron Moderate
- Calcium + Carbonyl iron Moderate
- Carbidopa-entacapone-levodopa + Carbonyl iron Moderate
Frequently asked questions
Can I take Carbonyl iron with Cimetidine?
MediHelp rates the interaction as moderate. Carbonyl iron and Cimetidine 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 acidity can impair absorption of non-heme oral iron. Long-term cimetidine use may therefore blunt the response to iron supplementation.
How serious is the interaction between Carbonyl iron and Cimetidine?
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 during prolonged co-therapy. Give iron with vitamin C or consider intravenous iron if response is poor.
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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