Drug interactions
Cimetidine + Lopinavir
Severity: Minor
Cimetidine and Lopinavir: minor 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 is a weak CYP3A inhibitor and might slightly increase lopinavir concentrations. Lopinavir is co-formulated with ritonavir, which is a far stronger inhibitor, so any added effect of cimetidine is likely small.
What this interaction means in plain words
Cimetidine and Lopinavir have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Cimetidine belongs to Gastrointestinal Tract; Lopinavir belongs to Anti Virals.
Why it happens
Weak CYP3A4 inhibition by cimetidine on top of ritonavir boosting.
What to do
No dose adjustment is usually needed; monitor for lopinavir adverse effects such as QT or PR prolongation if risk factors exist.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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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 Lopinavir
- Alfuzosin + Lopinavir Contraindicated
- Avanafil + Lopinavir Contraindicated
- Cisapride + Lopinavir Contraindicated
- Dronedarone + Lopinavir Contraindicated
- Eletriptan + Lopinavir Contraindicated
- Eplerenone + Lopinavir Contraindicated
Frequently asked questions
Can I take Cimetidine with Lopinavir?
MediHelp rates the interaction as minor. Cimetidine and Lopinavir have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Cimetidine is a weak CYP3A inhibitor and might slightly increase lopinavir concentrations. Lopinavir is co-formulated with ritonavir, which is a far stronger inhibitor, so any added effect of cimetidine is likely small.
How serious is the interaction between Cimetidine and Lopinavir?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No dose adjustment is usually needed; monitor for lopinavir adverse effects such as QT or PR prolongation if risk factors exist.
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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