Exemestane and Tamoxifen interaction
Exemestane and Tamoxifen: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Exemestane label · effective 2025-12-24
Percent Change in BMD from Baseline to 24 months, Exemestane vs. Control 1 IES 027 BMD Exemestane N=29 Tamoxifen 1 N=38 Exemestane N=59 Placebo 1 N=65 Lumbar spine (%) -3.1 -0.2 -3.5 -2.4 Femoral neck (%) -4.2 -0.3 -4.6 -2.6 During adjuvant treatment with exemestane, women with osteoporosis or at risk of osteoporosis should have their bone mineral density formally…
Laboratory Abnormalities In patients with early breast cancer, the incidence of hematological abnormalities of Common Toxicity Criteria (CTC) grade ≥1 was lower in the exemestane treatment group, compared with tamoxifen.
CTC grade 3–4 increases in bilirubin occurred in 0.9% of exemestane treated patients compared to 0.1% of tamoxifen treated patients.
Table 1 describes changes in BMD from baseline to 24 months in patients receiving exemestane compared to patients receiving tamoxifen (IES) or placebo (027).
In patients with early breast cancer, elevations in bilirubin, alkaline phosphatase, and creatinine were more common in those receiving exemestane than either tamoxifen or placebo.
From the Tamoxifen (SOLTAMOX) label · effective 2021-11-29
Aromatase Inhibitors Anastrozole The combination of anastrozole and tamoxifen did not demonstrate any benefit when compared to tamoxifen alone and should be avoided in all patients [see Clinical Studies (14.2) ] .
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
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.