Drug interactions
Cimetidine + Clarithromycin
Severity: Minor
Cimetidine and Clarithromycin: 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
Both drugs may modestly raise each other's concentrations through metabolic and transporter effects. Clinical consequences are usually limited, though clarithromycin adverse effects or QT effects could be amplified in susceptible patients.
What this interaction means in plain words
Cimetidine and Clarithromycin 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; Clarithromycin belongs to Anti Bacterial.
Why it happens
Cimetidine inhibits CYP3A4 and clarithromycin inhibits P-glycoprotein, altering clearance of each other.
What to do
No routine adjustment is needed. Monitor for gastrointestinal effects and QT risk factors in vulnerable patients.
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 Clarithromycin
- Astemizole + Clarithromycin Contraindicated
- Avanafil + Clarithromycin Contraindicated
- Cisapride + Clarithromycin Contraindicated
- Clarithromycin + Colchicine Contraindicated
- Clarithromycin + Conivaptan Contraindicated
- Clarithromycin + Dihydroergotamine Contraindicated
Frequently asked questions
Can I take Cimetidine with Clarithromycin?
MediHelp rates the interaction as minor. Cimetidine and Clarithromycin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Both drugs may modestly raise each other's concentrations through metabolic and transporter effects. Clinical consequences are usually limited, though clarithromycin adverse effects or QT effects could be amplified in susceptible patients.
How serious is the interaction between Cimetidine and Clarithromycin?
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 routine adjustment is needed. Monitor for gastrointestinal effects and QT risk factors in vulnerable 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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