Drug interactions
Cimetidine + Dutasteride-tamsulosin
Severity: Moderate
Cimetidine and Dutasteride-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 inhibits several CYP enzymes including CYP2D6 and CYP3A4 and reduces tamsulosin clearance, raising its exposure. It may also modestly raise dutasteride levels. The result may be more dizziness and orthostatic hypotension.
What this interaction means in plain words
Cimetidine and Dutasteride-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; Dutasteride-tamsulosin belongs to Genitourinary.
Why it happens
Cimetidine inhibits CYP2D6 and CYP3A4 and reduces tamsulosin clearance.
What to do
Monitor for orthostatic hypotension and consider an alternative acid suppressant such as a proton pump inhibitor or famotidine. Reduce the tamsulosin dose if symptoms occur.
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 Dutasteride-tamsulosin
Other interactions of Cimetidine
- Cimetidine + Dofetilide Contraindicated
- Cimetidine + Fezolinetant Contraindicated
- Alfentanil + Cimetidine Major
- Atazanavir + Cimetidine Major
- Carmustine + Cimetidine Major
- Cimetidine + Citalopram Major
Frequently asked questions
Can I take Cimetidine with Dutasteride-tamsulosin?
MediHelp rates the interaction as moderate. Cimetidine and Dutasteride-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 inhibits several CYP enzymes including CYP2D6 and CYP3A4 and reduces tamsulosin clearance, raising its exposure. It may also modestly raise dutasteride levels. The result may be more dizziness and orthostatic hypotension.
How serious is the interaction between Cimetidine and Dutasteride-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: Monitor for orthostatic hypotension and consider an alternative acid suppressant such as a proton pump inhibitor or famotidine. Reduce the tamsulosin dose if symptoms occur.
What other medicines interact with Dutasteride-tamsulosin?
MediHelp also lists interactions of Dutasteride-tamsulosin with, for example, Alfuzosin, Amifostine, Atazanavir. The full list is on the Dutasteride-tamsulosin page.
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