What the FDA labels say about taking them together
Paroxetine and tamoxifen
Paroxetine's FDA label of February 12, 2026 names tamoxifen in its drug interactions section, and tamoxifen's label names paroxetine too. The paroxetine label: “Reduce dosage of drugs metabolized by CYP2D6 as warranted. Concomitant use with Tamoxifen:”
Check it at the source: the paroxetine FDA label on DailyMed (effective February 12, 2026, Mylan Pharmaceuticals Inc.); the tamoxifen FDA label on DailyMed (effective December 18, 2025, Actavis Pharma, Inc.).
What does the paroxetine label say about tamoxifen?
Paroxetine label, drug interactionsClinical Impact; Concomitant use of tamoxifen with paroxetine tablets may lead to reduced plasma concentrations of the active metabolite (endoxifen) and reduced efficacy of tamoxifen
Paroxetine label, warnings and precautionsEfficacy of Tamoxifen Some studies have shown that the efficacy of tamoxifen, as measured by the risk of breast cancer relapse/mortality, may be reduced with concomitant use of paroxetine tablets as a result of paroxetine’s irreversible inhibition of CYP2D6 and lower blood levels of tamoxifen [see Drug Interactions (7) ].
Paroxetine Hydrochloride label (Apotex Corp, September 16, 2026), drug interactionsReduce dosage of drugs metabolized by CYP2D6 as warranted. ( 7 ) Concomitant use with Tamoxifen:
Brisdelle label (Legacy Pharma USA, Inc., April 28, 2025), drug interactionsTamoxifen Reduced plasma concentrations of active tamoxifen metabolite Consider avoiding concomitant use of tamoxifen and BRISDELLE.
Brisdelle label (Legacy Pharma USA, Inc., April 28, 2025), warnings and precautionsEfficacy of tamoxifen may be reduced when administered concomitantly with BRISDELLE ( 5.3 , 7.1 ) Abnormal Bleeding:
Source: FDA drug label (Paroxetine Hydrochloride, NDA020936), Apotex Corp, effective September 16, 2026 (SPL set 087ff0d3-1761-47ea-a8c1-7c4cb679af97), via openFDA
Source: FDA drug label (Paroxetine), Mylan Pharmaceuticals Inc., effective February 12, 2026 (SPL set 89dd7e24-85fc-4152-89ea-47ec2b48a1ed), via openFDA; the full label on DailyMed
What does the tamoxifen label say about paroxetine?
Soltamox label (Mayne Pharma, November 29, 2021), drug interactionsInhibitors of CYP2D6 The impact on the efficacy of tamoxifen with co-administration of strong CYP2D6 inhibitors (e.g., paroxetine) is not well established.
Source: FDA drug label (Soltamox, NDA021807), Mayne Pharma, effective November 29, 2021 (SPL set 1e6ff055-590c-41e6-9530-1fdf04cdbd02), via openFDA
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
| Paroxetine | Tamoxifen | |
|---|---|---|
| Labeled for | Depression, Anxiety, Menopause symptoms | Breast cancer |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.0611 per tablet 20 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