Drug interactions
Cimetidine + Lumefantrine
Severity: Moderate
Cimetidine and Lumefantrine: 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
Lumefantrine is metabolised by CYP3A4 and prolongs the QT interval. Cimetidine could modestly raise lumefantrine levels, adding to QT risk.
What this interaction means in plain words
Cimetidine and Lumefantrine 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
Weak CYP3A4 inhibition by cimetidine reduces lumefantrine metabolism.
What to do
Check for other QT-prolonging drugs and correct potassium and magnesium; consider ECG monitoring in at-risk patients.
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 Lumefantrine?
MediHelp rates the interaction as moderate. Cimetidine and Lumefantrine 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. Lumefantrine is metabolised by CYP3A4 and prolongs the QT interval. Cimetidine could modestly raise lumefantrine levels, adding to QT risk.
How serious is the interaction between Cimetidine and Lumefantrine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check for other QT-prolonging drugs and correct potassium and magnesium; consider ECG monitoring in at-risk patients.
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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