Fondaparinux and Alfalfa: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Fondaparinux
Alfalfa
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Reduced anticoagulant effectiveness
Interaction Deep Dive
Alfalfa contains the coumarin medicagol, which may add to the anticoagulant effect, and vitamin K, which may counteract it12. The clinical outcome of the combination of alfalfa and anticoagulants is unknown. It is thought that coagulation will only be affected if large doses or multiple combinations of herbs which affect coagulation are taken for a prolonged period of time 1.
Why it happens (mechanism)
Vitamin K content of alfalfa counteracts the effectiveness of anticoagulants
Common questions
Can I take Fondaparinux and Alfalfa together?
Reduced anticoagulant effectiveness Always confirm with your pharmacist or prescriber before making any change.
How serious is the Fondaparinux and Alfalfa interaction?
It is rated minor. Usually limited clinical impact.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Fondaparinux or Alfalfa need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (2)
- Norred CL & Brinker F: Potential coagulation effects of preoperative complementary and alternative medicines. Alt Ther 2001; 7(6):58-67.
- Newall CA, Anderson LA, & Phillipson JDNewall CA, Anderson LA, & Phillipson JD: Herbal Medicines: A Guide for Healthcare Professionals, The Pharmaceutical Press, London, England, 1996, pp 23,282.
Keep reading about Fondaparinux
Keep reading about Alfalfa
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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