Drug interactions
Tamoxifen + Verapamil
Severity: Minor
Tamoxifen and Verapamil: 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
Verapamil may alter tamoxifen metabolism, increasing parent drug levels. Clinical consequences are uncertain and likely small.
What this interaction means in plain words
Tamoxifen and Verapamil have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Tamoxifen belongs to Endocrine; Verapamil belongs to Cardiovascular.
Why it happens
Verapamil inhibits CYP3A4, reducing conversion of tamoxifen to N-desmethyltamoxifen.
What to do
No routine dose change is needed. Monitor for tamoxifen adverse effects and clinical response.
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 Verapamil
- Dofetilide + Verapamil Contraindicated
- Flibanserin + Verapamil Contraindicated
- Lomitapide + Verapamil Contraindicated
- Lonafarnib + Verapamil Contraindicated
- Pimozide + Verapamil Contraindicated
- Acebutolol + Verapamil Major
Other interactions of Tamoxifen
- Amiodarone + Tamoxifen Major
- Anastrozole + Tamoxifen Major
- Bupropion + Tamoxifen Major
- Carbamazepine + Tamoxifen Major
- Cinacalcet + Tamoxifen Major
- Dacomitinib + Tamoxifen Major
Frequently asked questions
Can I take Tamoxifen with Verapamil?
MediHelp rates the interaction as minor. Tamoxifen and Verapamil have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Verapamil may alter tamoxifen metabolism, increasing parent drug levels. Clinical consequences are uncertain and likely small.
How serious is the interaction between Tamoxifen and Verapamil?
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 routine dose change is needed. Monitor for tamoxifen adverse effects and clinical response.
What other medicines interact with Verapamil?
MediHelp also lists interactions of Verapamil with, for example, Dofetilide, Flibanserin, Lomitapide. The full list is on the Verapamil page.
Full monographs, dosing and an interaction checker in the MediHelp app
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