What the FDA labels say about taking them together
Chloroquine and tamoxifen
Chloroquine's FDA label of July 2, 2026 names tamoxifen in its warnings section; the tamoxifen labels PlainMeds reads (2) do not name chloroquine. The chloroquine label: “… subnormal glomerular filtration, use of some concomitant drug products such as tamoxifen citrate (see PRECAUTIONS ), and concurrent macular disease.”
Check it at the source: the chloroquine FDA label on DailyMed (effective July 2, 2026, Rising Pharma Holdings, Inc.); the tamoxifen FDA label on DailyMed (effective December 18, 2025, Actavis Pharma, Inc.).
What does the chloroquine label say about tamoxifen?
Chloroquine label, warningsSignificant risk factors for retinal damage include daily doses of chloroquine phosphate greater than 2.3 mg/kg of actual body weight, durations of use greater than five years, subnormal glomerular filtration, use of some concomitant drug products such as tamoxifen citrate (see PRECAUTIONS ), and concurrent macular disease.
Source: FDA drug label (Chloroquine Phosphate), Rising Pharma Holdings, Inc., effective July 2, 2026 (SPL set 06c69e2b-211b-4746-9f3a-f86d36520570), via openFDA; the full label on DailyMed
What does the tamoxifen label say about chloroquine?
Tamoxifen's label (effective December 18, 2025) and its 1 other brand-application label do not name chloroquine 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
| Chloroquine | Tamoxifen | |
|---|---|---|
| Labeled for | n/a | Breast cancer |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $6.65 per tablet 500 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