Tamoxifen and Bupropion Interaction
Drug interaction information between Tamoxifen and Bupropion.
Tamoxifen and Bupropion have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Tamoxifen and Bupropion. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Bupropion prevents tamoxifen from being changed into its active form, which could make the tamoxifen less effective at treating cancer.
FDA Label Information
Drugs that require metabolic activation by CYP2D6 to be effective (e.g., tamoxifen), theoretically could have reduced efficacy when administered concomitantly with inhibitors of CYP2D6 such as bupropion.
Tamoxifen Also Interacts With
- Warfarin major
- Anastrozole major
- Letrozole moderate
- Desvenlafaxine minor
- Letrozole (Fertility) minor
Bupropion Also Interacts With
- Tranylcypromine major
- Theophylline moderate
- Isavuconazonium moderate
- Metoprolol minor
- Sertraline minor
Frequently Asked Questions
What SPL severity band is on file for Tamoxifen + Bupropion?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Bupropion has 35 labeled pairs on file vs Tamoxifen's 10. In the minor band specifically: Tamoxifen has 7 (also Desvenlafaxine, Letrozole, Levothyroxine, Liothyronine); Bupropion has 32 (also Metoprolol, Sertraline, Fluoxetine, Clopidogrel).
What mechanism field is on file for Tamoxifen and Bupropion?
Bupropion prevents tamoxifen from being changed into its active form, which could make the tamoxifen less effective at treating cancer.
Tamoxifen carries more major-labeled pairs than Bupropion
SPL source-record counts only. This page's band is minor · classes on file: Tamoxifen (Selective Estrogen Receptor Modulator (SERM)); Bupropion (Norepinephrine-Dopamine Reuptake Inhibitor (NDRI)).
Tamoxifen has 2 major-labeled pairs vs Bupropion's 1. This page itself is in the minor band, not the major band.
2 major · 1 moderate · 7 minor · 10 total
- Other minor peers for Tamoxifen
- Desvenlafaxine
- Letrozole
- Levothyroxine
- Liothyronine
1 major · 2 moderate · 32 minor · 35 total
- Other minor peers for Bupropion
- Metoprolol
- Sertraline
- Fluoxetine
- Clopidogrel
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.