Warfarin and Fluoxetine Interaction
Drug interaction information between Warfarin and Fluoxetine.
Warfarin and Fluoxetine have a documented major interaction in FDA labeling.
FDA drug labeling documents a major-severity interaction between Warfarin and Fluoxetine. 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
Fluoxetine can change how your blood thinner works and affect how your blood clots, making it more likely for you to bleed.
FDA Label Information
NSAIDs, Aspirin, Warfarin): May potentiate the risk of bleeding ( 7.4 ) Drugs Tightly Bound to Plasma Proteins: May cause a shift in plasma concentrations ( 7.6 , 7.7 ) Olanzapine: When used in combination with fluoxetine, also refer to the Drug Interactions section of the package insert for Symbyax ( 7.7 ) Drugs that Prolong the QT Interval: Do not use fluoxetine with thioridazine or pimozide. 7.4 Drugs that Interfere with Hemostasis (e.g., NSAIDs, Aspirin, Warfarin) Serotonin release by platelets plays an important role in hemostasis. Altered anticoagulant effects, including increased...
Warfarin Also Interacts With
- Tamoxifen major
- Ibuprofen moderate
- Aspirin moderate
- Diclofenac moderate
- Desvenlafaxine moderate
Fluoxetine Also Interacts With
- Aspirin major
- Olanzapine major
- Pimozide major
- Thioridazine major
- Clonazepam major
Frequently Asked Questions
What SPL severity band is on file for Warfarin + Fluoxetine?
Compiled FDA labeling labels this pair major. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Warfarin has 163 labeled pairs on file vs Fluoxetine's 68. In the major band specifically: Warfarin has 2 (also Tamoxifen); Fluoxetine has 6 (also Aspirin, Olanzapine, Pimozide, Thioridazine).
What mechanism field is on file for Warfarin and Fluoxetine?
Fluoxetine can change how your blood thinner works and affect how your blood clots, making it more likely for you to bleed.
Fluoxetine carries more major-labeled pairs than Warfarin
SPL source-record counts only. This page's band is major · classes on file: Warfarin (Vitamin K Antagonist (Anticoagulant)); Fluoxetine (Selective Serotonin Reuptake Inhibitor (SSRI)).
Fluoxetine has 6 major-labeled pairs vs Warfarin's 2.
6 major · 19 moderate · 43 minor · 68 total
- Other major peers for Fluoxetine
- Aspirin
- Olanzapine
- Pimozide
- Thioridazine
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.