Drug interactions
Cimetidine + Irinotecan liposomal
Severity: Moderate
Cimetidine and Irinotecan liposomal: 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 could increase exposure to irinotecan and its active metabolite SN-38 through CYP3A4 inhibition, raising the risk of neutropenia and diarrhea. However, CYP3A4 inhibition also decreases formation of SN-38 from oxidative metabolites, so the net effect is uncertain.
What this interaction means in plain words
Cimetidine and Irinotecan liposomal 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.
Why it happens
Cimetidine inhibits CYP3A4, altering irinotecan oxidative metabolism; the net clinical effect is not well established.
What to do
Prefer famotidine as an alternative acid suppressant. If combined, monitor blood counts and diarrhea.
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
Frequently asked questions
Can I take Cimetidine with Irinotecan liposomal?
MediHelp rates the interaction as moderate. Cimetidine and Irinotecan liposomal 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 could increase exposure to irinotecan and its active metabolite SN-38 through CYP3A4 inhibition, raising the risk of neutropenia and diarrhea. However, CYP3A4 inhibition also decreases formation of SN-38 from oxidative metabolites, so the net effect is uncertain.
How serious is the interaction between Cimetidine and Irinotecan liposomal?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer famotidine as an alternative acid suppressant. If combined, monitor blood counts and diarrhea.
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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