Drug interactions
Cimetidine + Encainide
Severity: Minor
Cimetidine and Encainide: 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 may reduce CYP2D6-mediated conversion of encainide to its active metabolites, altering its antiarrhythmic effect. Encainide is no longer widely marketed, so the interaction is rarely relevant.
What this interaction means in plain words
Cimetidine and Encainide have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Cimetidine inhibits CYP2D6, which metabolizes encainide to active metabolites.
What to do
If encainide is used, monitor ECG and antiarrhythmic response when cimetidine is started or stopped.
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
Frequently asked questions
Can I take Cimetidine with Encainide?
MediHelp rates the interaction as minor. Cimetidine and Encainide 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 may reduce CYP2D6-mediated conversion of encainide to its active metabolites, altering its antiarrhythmic effect. Encainide is no longer widely marketed, so the interaction is rarely relevant.
How serious is the interaction between Cimetidine and Encainide?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: If encainide is used, monitor ECG and antiarrhythmic response when cimetidine is started or stopped.
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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