Drug interactions
Bupropion + Tamoxifen
Severity: Major
Bupropion and Tamoxifen: major 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
Bupropion is a strong CYP2D6 inhibitor and can reduce conversion of tamoxifen to endoxifen, its most active metabolite. Lower endoxifen exposure may reduce the anti-estrogen effect and potentially the breast cancer treatment benefit.
What this interaction means in plain words
Bupropion and Tamoxifen can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Bupropion belongs to Central Nervous System; Tamoxifen belongs to Endocrine.
Why it happens
Bupropion and its metabolites inhibit CYP2D6, reducing tamoxifen bioactivation to endoxifen.
What to do
Avoid the combination where possible and choose an antidepressant with minimal CYP2D6 inhibition, such as venlafaxine, citalopram, or mirtazapine. If bupropion is essential, review the choice with the oncology team.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Bupropion
- Bupropion + Isocarboxazid Contraindicated
- Bupropion + Linezolid Contraindicated
- Bupropion + Phenelzine Contraindicated
- Bupropion + Rasagiline Contraindicated
- Bupropion + Selegiline Contraindicated
- Bupropion + Selegiline transdermal Contraindicated
Other interactions of Tamoxifen
- Amiodarone + Tamoxifen Major
- Anastrozole + Tamoxifen Major
- Carbamazepine + Tamoxifen Major
- Cinacalcet + Tamoxifen Major
- Dacomitinib + Tamoxifen Major
- Eliglustat + Tamoxifen Major
Frequently asked questions
Can I take Bupropion with Tamoxifen?
MediHelp rates the interaction as major. Bupropion and Tamoxifen can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Bupropion is a strong CYP2D6 inhibitor and can reduce conversion of tamoxifen to endoxifen, its most active metabolite. Lower endoxifen exposure may reduce the anti-estrogen effect and potentially the breast cancer treatment benefit.
How serious is the interaction between Bupropion and Tamoxifen?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible and choose an antidepressant with minimal CYP2D6 inhibition, such as venlafaxine, citalopram, or mirtazapine. If bupropion is essential, review the choice with the oncology team.
What other medicines interact with Bupropion?
MediHelp also lists interactions of Bupropion with, for example, Isocarboxazid, Linezolid, Phenelzine. The full list is on the Bupropion page.
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