Letrozole interactions
Letrozole (Femara), an aromatase inhibitor has 4 documented interactions across the FDA labels and fact sheets we index: 1 major, 1 moderate, 0 minor, and 2 where a label reports no significant interaction. Each entry below quotes the sentence behind it. This drug page is a starting point, not a verdict for your situation.
Major interactions (1)
Anastrozole and letrozole: Should not be used in combination with tamoxifen. (Tamoxifen label, Drug interactions)
Moderate interactions (1)
- PalbociclibCYP3A4 inhibitorModerate
A Grade ≥3 decrease in neutrophil counts was reported in 66% of patients receiving IBRANCE plus letrozole in PALOMA-2 and 66% of patients receiving IBRANCE plus fulvestrant in PALOMA-3. (Palbociclib label, Warnings and precautions)
No significant interaction reported (2)
- CimetidineH2 blockerNo interaction
Cimetidine A pharmacokinetic interaction study with cimetidine (Study P004) showed no clinically significant effect on letrozole pharmacokinetics. (Letrozole label, Drug interactions)
Warfarin An interaction study (P017) with warfarin showed no clinically significant effect of letrozole on warfarin pharmacokinetics. (Letrozole label, Drug interactions)
Check Letrozole against everything you take. Add your full list; every pair is checked at once.
Open in the checkerNot medical advice. Severity reflects the label's wording, not your circumstances. A "major" flag can be routine under supervision and a "minor" one can matter at high doses. Ask a pharmacist.