Letrozole and Cimetidine Interaction
Drug interaction information between Letrozole and Cimetidine.
Letrozole and Cimetidine have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Letrozole and Cimetidine. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Cimetidine does not have a significant effect on how letrozole moves through your body. The two drugs do not interfere with each other in a meaningful way.
FDA Label Information
Cimetidine A pharmacokinetic interaction study with cimetidine (study P004) showed no clinically significant effect on letrozole pharmacokinetics.
Letrozole Also Interacts With
- Tamoxifen moderate
- Warfarin minor
- Letrozole (Fertility) minor
Cimetidine Also Interacts With
- Levofloxacin major
- Posaconazole major
- Risperidone major
- Valproate major
- Empagliflozin moderate
Frequently Asked Questions
What SPL severity band is on file for Letrozole + Cimetidine?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Cimetidine has 77 labeled pairs on file vs Letrozole's 4. In the minor band specifically: Letrozole has 3 (also Warfarin, Letrozole); Cimetidine has 63 (also Albendazole, Alogliptin, Alosetron, Alprazolam).
What mechanism field is on file for Letrozole and Cimetidine?
Cimetidine does not have a significant effect on how letrozole moves through your body. The two drugs do not interfere with each other in a meaningful way.
Cimetidine carries more major-labeled pairs than Letrozole
SPL source-record counts only. This page's band is minor · classes on file: Letrozole (Aromatase Inhibitor); Cimetidine (H2 Receptor Antagonist).
Cimetidine has 4 major-labeled pairs vs Letrozole's 0. This page itself is in the minor band, not the major band.
0 major · 1 moderate · 3 minor · 4 total
4 major · 10 moderate · 63 minor · 77 total
- Other minor peers for Cimetidine
- Albendazole
- Alogliptin
- Alosetron
- Alprazolam
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.