Drug interactions
Cimetidine + Tamsulosin
Severity: Moderate
Cimetidine and Tamsulosin: 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 raises tamsulosin exposure by a moderate amount and reduces its clearance. This may increase orthostatic hypotension, dizziness and syncope, especially in older men.
What this interaction means in plain words
Cimetidine and Tamsulosin 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; Tamsulosin belongs to Genitourinary.
Why it happens
Cimetidine inhibits CYP2D6 and CYP3A4 metabolism of tamsulosin and reduces its clearance.
What to do
Use cautiously in patients with a history of orthostasis or reduced CYP2D6 activity; monitor blood pressure and counsel on dizziness. Consider famotidine as an alternative.
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 Tamsulosin
- Alfuzosin + Tamsulosin Major
- Avanafil + Tamsulosin Major
- Ceritinib + Tamsulosin Major
- Clarithromycin + Tamsulosin Major
- Cobicistat + Tamsulosin Major
- Doxazosin + Tamsulosin Major
Frequently asked questions
Can I take Cimetidine with Tamsulosin?
MediHelp rates the interaction as moderate. Cimetidine and Tamsulosin 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 raises tamsulosin exposure by a moderate amount and reduces its clearance. This may increase orthostatic hypotension, dizziness and syncope, especially in older men.
How serious is the interaction between Cimetidine and Tamsulosin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use cautiously in patients with a history of orthostasis or reduced CYP2D6 activity; monitor blood pressure and counsel on dizziness. Consider famotidine as an alternative.
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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