Chloroquine and Tamoxifen interaction
Chloroquine and Tamoxifen: the Chloroquine prescribing label flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Chloroquine (Chloroquine Phosphate) label · effective 2026-01-13
Tamoxifen: Concomitant use of chloroquine with drugs known to induce retinal toxicity such as tamoxifen is not recommended (see WARNINGS ).
Significant 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.
For individuals with significant risk factors (daily dose of chloroquine phosphate greater than 2.3 mg/kg of actual body weight, subnormal glomerular filtration, use of tamoxifen citrate or concurrent macular disease) monitoring should include annual examinations which include BCVA, VF and SD-OCT.
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.