Drug interactions
Cimetidine + Tofacitinib
Severity: Minor
Cimetidine and Tofacitinib: 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 alone is a weak inhibitor and is not expected to change tofacitinib exposure meaningfully. Dose reduction is advised only for combined moderate CYP3A4 and potent CYP2C19 inhibition.
What this interaction means in plain words
Cimetidine and Tofacitinib 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; Tofacitinib belongs to Musculoskeletal.
Why it happens
Cimetidine weakly inhibits CYP3A4 and CYP2C19, which participate in tofacitinib metabolism.
What to do
No dose adjustment is generally needed; monitor for infections and cytopenias as routine.
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 Tofacitinib
- Baricitinib + Tofacitinib Contraindicated
- Cladribine + Tofacitinib Contraindicated
- Tofacitinib + Upadacitinib Contraindicated
- Abatacept + Tofacitinib Major
- Anti-thymocyte + Tofacitinib Major
- Antithymocyte globulin equine + Tofacitinib Major
Frequently asked questions
Can I take Cimetidine with Tofacitinib?
MediHelp rates the interaction as minor. Cimetidine and Tofacitinib 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 alone is a weak inhibitor and is not expected to change tofacitinib exposure meaningfully. Dose reduction is advised only for combined moderate CYP3A4 and potent CYP2C19 inhibition.
How serious is the interaction between Cimetidine and Tofacitinib?
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 dose adjustment is generally needed; monitor for infections and cytopenias as routine.
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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