Drug interactions
Cimetidine + Diclofenac
Severity: Minor
Cimetidine and Diclofenac: 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 slightly increase diclofenac exposure, but no clinically important effect has been established. Cimetidine also does not reliably protect against NSAID gastrointestinal injury.
What this interaction means in plain words
Cimetidine and Diclofenac 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; Diclofenac belongs to Musculoskeletal.
Why it happens
Cimetidine weakly inhibits CYP2C9, which metabolizes diclofenac.
What to do
No routine adjustment is needed; use the lowest effective diclofenac dose and monitor for gastrointestinal and renal adverse effects.
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 Diclofenac
- Diclofenac + Ketorolac Contraindicated
- Diclofenac + Ketorolac intranasal Contraindicated
- Aceclofenac + Diclofenac Major
- Acemetacin + Diclofenac Major
- Alteplase + Diclofenac Major
- Amiloride + Diclofenac Major
Frequently asked questions
Can I take Cimetidine with Diclofenac?
MediHelp rates the interaction as minor. Cimetidine and Diclofenac 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 slightly increase diclofenac exposure, but no clinically important effect has been established. Cimetidine also does not reliably protect against NSAID gastrointestinal injury.
How serious is the interaction between Cimetidine and Diclofenac?
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; use the lowest effective diclofenac dose and monitor for gastrointestinal and renal adverse effects.
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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