Citalopram and Warfarin Interaction
Drug interaction information between Citalopram and Warfarin.
Citalopram and Warfarin have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Citalopram and Warfarin. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Citalopram can change how warfarin works in your body, which may affect how quickly your blood is able to clot.
What To Do
Your doctor should closely monitor your blood clotting levels, also known as the INR, while you are taking both of these medications.
FDA Label Information
For patients taking warfarin, carefully monitor the international normalized ratio [see Warning and Precautions (5.4) ].
Citalopram Also Interacts With
- Linezolid major
- Pimozide major
- Escitalopram major
- Phenelzine moderate
- Buspirone minor
Warfarin Also Interacts With
- Fluoxetine major
- Tamoxifen major
- Ibuprofen moderate
- Aspirin moderate
- Diclofenac moderate
Frequently Asked Questions
Can I take Citalopram and Warfarin together?
This is a moderate interaction. Your doctor should closely monitor your blood clotting levels, also known as the INR, while you are taking both of these medications.
How serious is the interaction between Citalopram and Warfarin?
This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.
Why do Citalopram and Warfarin interact?
Citalopram can change how warfarin works in your body, which may affect how quickly your blood is able to clot.
Understanding the Citalopram and Warfarin Interaction
FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Citalopram belongs to the Selective Serotonin Reuptake Inhibitor (SSRI) class and Warfarin belongs to the Vitamin K Antagonist (Anticoagulant) class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Citalopram can change how warfarin works in your body, which may affect how quickly your blood is able to clot. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Citalopram has 9 total documented interactions on file in this dataset, and Warfarin has 163. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: Your doctor should closely monitor your blood clotting levels, also known as the INR, while you are taking both of these medications. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Citalopram or Warfarin based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.