Drug interactions
Naproxen + Phenindione
Severity: Major
Naproxen and Phenindione: major interaction.
Last updated
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 naproxen adds platelet inhibition and gastric mucosal injury. The combination markedly increases bleeding risk, particularly gastrointestinal hemorrhage.
What this interaction means in plain words
Naproxen 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 pharmacodynamic effect of anticoagulation and NSAID platelet inhibition, with possible protein-binding displacement.
What to do
Avoid the combination where possible and use paracetamol for pain. If it is unavoidable, monitor INR and bleeding signs and consider gastroprotection.
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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Other interactions of Naproxen
- Ketorolac intranasal + Naproxen Contraindicated
- Ketorolac + Naproxen Contraindicated
- Aceclofenac + Naproxen Major
- Acemetacin + Naproxen Major
- Acetylsalicylic acid + Naproxen Major
- Alteplase + Naproxen Major
Frequently asked questions
Can I take Naproxen with Phenindione?
MediHelp rates the interaction as major. Naproxen 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 naproxen adds platelet inhibition and gastric mucosal injury. The combination markedly increases bleeding risk, particularly gastrointestinal hemorrhage.
How serious is the interaction between Naproxen 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: Avoid the combination where possible and use paracetamol for pain. If it is unavoidable, monitor INR and bleeding signs and consider gastroprotection.
What other medicines interact with Naproxen?
MediHelp also lists interactions of Naproxen with, for example, Ketorolac intranasal, Ketorolac, Aceclofenac. The full list is on the Naproxen page.
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