Drug interactions
Cimetidine + Duloxetine
Severity: Moderate
Cimetidine and Duloxetine: 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 inhibits CYP1A2, the main route of duloxetine metabolism, which can raise duloxetine exposure. This may increase nausea, dizziness, blood pressure elevation and other dose-related adverse effects.
What this interaction means in plain words
Cimetidine and Duloxetine 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; Duloxetine belongs to Central Nervous System.
Why it happens
Cimetidine inhibits CYP1A2 (and to some extent CYP2D6), reducing duloxetine clearance.
What to do
Monitor for duloxetine adverse effects and blood pressure, and lower the dose if needed. Consider famotidine as an alternative acid suppressant.
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 Duloxetine
- Duloxetine + Isocarboxazid Contraindicated
- Duloxetine + Linezolid Contraindicated
- Duloxetine + Methylene blue Contraindicated
- Duloxetine + Phenelzine Contraindicated
- Duloxetine + Procarbazine Contraindicated
- Duloxetine + Rasagiline Contraindicated
Frequently asked questions
Can I take Cimetidine with Duloxetine?
MediHelp rates the interaction as moderate. Cimetidine and Duloxetine 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 inhibits CYP1A2, the main route of duloxetine metabolism, which can raise duloxetine exposure. This may increase nausea, dizziness, blood pressure elevation and other dose-related adverse effects.
How serious is the interaction between Cimetidine and Duloxetine?
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 duloxetine adverse effects and blood pressure, and lower the dose if needed. Consider famotidine as an alternative acid suppressant.
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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