Drug interactions
Cimetidine + Fluconazole
Severity: Minor
Cimetidine and Fluconazole: 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
Fluconazole inhibits some enzymes that metabolize cimetidine, which could slightly raise cimetidine levels. Cimetidine has a wide safety margin, so this is rarely significant.
What this interaction means in plain words
Cimetidine and Fluconazole 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; Fluconazole belongs to Anti Fungals.
Why it happens
Fluconazole inhibits CYP2C19 and related pathways involved in cimetidine metabolism.
What to do
No routine action is needed; monitor for cimetidine adverse effects such as confusion in elderly or renally impaired 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 Fluconazole
- Dihydroergotamine intranasal + Fluconazole Contraindicated
- Dihydroergotamine + Fluconazole Contraindicated
- Dofetilide + Fluconazole Contraindicated
- Domperidone + Fluconazole Contraindicated
- Dronedarone + Fluconazole Contraindicated
- Erythromycin + Fluconazole Contraindicated
Frequently asked questions
Can I take Cimetidine with Fluconazole?
MediHelp rates the interaction as minor. Cimetidine and Fluconazole have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Fluconazole inhibits some enzymes that metabolize cimetidine, which could slightly raise cimetidine levels. Cimetidine has a wide safety margin, so this is rarely significant.
How serious is the interaction between Cimetidine and Fluconazole?
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 action is needed; monitor for cimetidine adverse effects such as confusion in elderly or renally impaired 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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