Drug interactions
Cimetidine + Pirfenidone
Severity: Moderate
Cimetidine and Pirfenidone: moderate 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 can raise pirfenidone exposure, increasing the risk of nausea, rash, photosensitivity and liver enzyme elevation. Labeling advises caution with moderate CYP1A2 inhibitors.
What this interaction means in plain words
Cimetidine and Pirfenidone can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Cimetidine belongs to Gastrointestinal Tract; Pirfenidone belongs to Miscellaneous.
Why it happens
Cimetidine inhibits CYP1A2, the main enzyme metabolizing pirfenidone.
What to do
Monitor for adverse effects and liver tests, and reduce the pirfenidone dose if intolerance occurs. Prefer famotidine or a PPI.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Pirfenidone
Frequently asked questions
Can I take Cimetidine with Pirfenidone?
MediHelp rates the interaction as moderate. Cimetidine and Pirfenidone can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Cimetidine can raise pirfenidone exposure, increasing the risk of nausea, rash, photosensitivity and liver enzyme elevation. Labeling advises caution with moderate CYP1A2 inhibitors.
How serious is the interaction between Cimetidine and Pirfenidone?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for adverse effects and liver tests, and reduce the pirfenidone dose if intolerance occurs. Prefer famotidine or a PPI.
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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