Does Tamoxifen Interact with Letrozole?
CDI records a moderate classification for Tamoxifen and Letrozole. The stored summary is: Coadministration reduces letrozole plasma levels by 38% on average, but clinical experience indicates therapeutic effect is not impaired when letrozole is administered immediately after tamoxifen. The mechanism involves reduction of letrozole plasma levels. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This record was extracted from drug labeling through openFDA. NIH/NLM RxNorm is used for drug identities. The summary and severity classification are CDI's processed information, not a verbatim source quotation. Product, route, and patient circumstances matter.
- Severity
- Moderate
- Letrozole Class
- Aromatase Inhibitor
- Management
- Monitor for effects
- Data Source
- U.S. FDA via OpenFDA
Recorded Mechanism
Reduction of letrozole plasma levels
What To Tell Your Doctor or Pharmacist
If you are taking Tamoxifen and your doctor is considering prescribing Letrozole (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Ask whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider