Drug interactions
Cimetidine + Gefitinib
Severity: Moderate
Cimetidine and Gefitinib: 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
Gefitinib absorption depends on gastric acidity, and H2 blockers can lower its exposure. Reduced exposure may compromise antitumor efficacy.
What this interaction means in plain words
Cimetidine and Gefitinib 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; Gefitinib belongs to Oncology.
Why it happens
Cimetidine raises gastric pH, decreasing gefitinib solubility and absorption.
What to do
Take gefitinib at least 12 hours after the last H2 antagonist dose and at least 6 hours before the next dose, or avoid acid suppression where possible.
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 Gefitinib
Frequently asked questions
Can I take Cimetidine with Gefitinib?
MediHelp rates the interaction as moderate. Cimetidine and Gefitinib 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. Gefitinib absorption depends on gastric acidity, and H2 blockers can lower its exposure. Reduced exposure may compromise antitumor efficacy.
How serious is the interaction between Cimetidine and Gefitinib?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Take gefitinib at least 12 hours after the last H2 antagonist dose and at least 6 hours before the next dose, or avoid acid suppression where possible.
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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