Drug interactions
Fondaparinux + Phenindione
Severity: Major
Fondaparinux and Phenindione: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Phenindione is a vitamin K antagonist and fondaparinux a factor Xa inhibitor, so together they increase bleeding risk. Overlap is intended only when transitioning to oral anticoagulation, and should be limited to that period.
What this interaction means in plain words
Fondaparinux and Phenindione can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Additive anticoagulation via reduced vitamin K-dependent factor synthesis and factor Xa inhibition.
What to do
Use overlap only as a bridging strategy and stop fondaparinux once the INR is therapeutic. Monitor INR and watch for bleeding.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Fondaparinux
- Defibrotide + Fondaparinux Contraindicated
- Fondaparinux + Ketorolac Contraindicated
- Abciximab + Fondaparinux Major
- Aceclofenac + Fondaparinux Major
- Acetylsalicylic acid + Fondaparinux Major
- Alteplase + Fondaparinux Major
Frequently asked questions
Can I take Fondaparinux with Phenindione?
MediHelp rates the interaction as major. Fondaparinux and Phenindione can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Phenindione is a vitamin K antagonist and fondaparinux a factor Xa inhibitor, so together they increase bleeding risk. Overlap is intended only when transitioning to oral anticoagulation, and should be limited to that period.
How serious is the interaction between Fondaparinux and Phenindione?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use overlap only as a bridging strategy and stop fondaparinux once the INR is therapeutic. Monitor INR and watch for bleeding.
What other medicines interact with Fondaparinux?
MediHelp also lists interactions of Fondaparinux with, for example, Defibrotide, Ketorolac, Abciximab. The full list is on the Fondaparinux page.
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