Drug interactions
Cimetidine + Famciclovir
Severity: Minor
Cimetidine and Famciclovir: 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
Famciclovir is converted to penciclovir partly by aldehyde oxidase, but clinical studies with cimetidine showed no relevant effect on penciclovir formation. No clinically meaningful interaction is expected.
What this interaction means in plain words
Cimetidine and Famciclovir 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; Famciclovir belongs to Anti Virals.
Why it happens
Theoretical aldehyde oxidase interference that has not been shown to be clinically relevant.
What to do
No adjustment of famciclovir is needed.
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 Famciclovir
Frequently asked questions
Can I take Cimetidine with Famciclovir?
MediHelp rates the interaction as minor. Cimetidine and Famciclovir have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Famciclovir is converted to penciclovir partly by aldehyde oxidase, but clinical studies with cimetidine showed no relevant effect on penciclovir formation. No clinically meaningful interaction is expected.
How serious is the interaction between Cimetidine and Famciclovir?
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 adjustment of famciclovir is needed.
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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