Drug interactions
Duloxetine + Tamoxifen
Severity: Moderate
Duloxetine and Tamoxifen: 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
Tamoxifen is converted by CYP2D6 to endoxifen, its most active metabolite. Duloxetine is a moderate CYP2D6 inhibitor and may reduce endoxifen formation, potentially lowering tamoxifen efficacy, although the clinical impact is less certain than with strong inhibitors.
What this interaction means in plain words
Duloxetine and Tamoxifen 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.
Duloxetine belongs to Central Nervous System; Tamoxifen belongs to Endocrine.
Why it happens
Duloxetine inhibits CYP2D6, decreasing conversion of tamoxifen to endoxifen.
What to do
Where possible, prefer an antidepressant with minimal CYP2D6 inhibition such as venlafaxine, citalopram or escitalopram in patients on tamoxifen. If duloxetine is necessary, use the lowest effective dose.
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 Duloxetine
- Duloxetine + Isocarboxazid Contraindicated
- Duloxetine + Linezolid Contraindicated
- Duloxetine + Methylene blue Contraindicated
- Duloxetine + Phenelzine Contraindicated
- Duloxetine + Procarbazine Contraindicated
- Duloxetine + Rasagiline Contraindicated
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 Duloxetine with Tamoxifen?
MediHelp rates the interaction as moderate. Duloxetine and Tamoxifen 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. Tamoxifen is converted by CYP2D6 to endoxifen, its most active metabolite. Duloxetine is a moderate CYP2D6 inhibitor and may reduce endoxifen formation, potentially lowering tamoxifen efficacy, although the clinical impact is less certain than with strong inhibitors.
How serious is the interaction between Duloxetine and Tamoxifen?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Where possible, prefer an antidepressant with minimal CYP2D6 inhibition such as venlafaxine, citalopram or escitalopram in patients on tamoxifen. If duloxetine is necessary, use the lowest effective dose.
What other medicines interact with Duloxetine?
MediHelp also lists interactions of Duloxetine with, for example, Isocarboxazid, Linezolid, Methylene blue. The full list is on the Duloxetine page.
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