What the FDA labels say about taking them together
Bupropion and tamoxifen
Bupropion's FDA label of June 21, 2024 names tamoxifen in its drug interactions section; the tamoxifen labels PlainMeds reads (2) do not name bupropion. The bupropion label: “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.”
Check it at the source: the bupropion FDA label on DailyMed (effective June 21, 2024); the tamoxifen FDA label on DailyMed (effective December 18, 2025, Actavis Pharma, Inc.).
What does the bupropion label say about tamoxifen?
Bupropion label, drug interactionsDrugs 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.
Source: FDA drug label (BUPROPION HYDROCHLORIDE), Epic Pharma LLC, effective June 21, 2024 (SPL set 9fb44e96-6160-4a4a-90cb-91764c0dcd89), via openFDA; the full label on DailyMed
What does the tamoxifen label say about bupropion?
Tamoxifen's label (effective December 18, 2025) and its 1 other brand-application label do not name bupropion in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Tamoxifen Citrate), Actavis Pharma, Inc., effective December 18, 2025 (SPL set 9b8a4211-120f-4981-ad69-928accb97637), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Bupropion | Tamoxifen | |
|---|---|---|
| Labeled for | Depression, Quitting smoking | Breast cancer |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.0785 per tablet 150 mg tablet | $0.277 per tablet 20 mg tablet |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once