Drug interactions
Diflunisal + Fondaparinux
Severity: Major
Diflunisal and Fondaparinux: major interaction.
Last updated Sources: EMA SmPC
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
Diflunisal inhibits platelet function and can irritate the gastric mucosa, so adding it to fondaparinux raises the risk of bleeding, particularly gastrointestinal bleeding. The risk is greater in older patients and those with renal impairment, in whom fondaparinux accumulates.
What this interaction means in plain words
Diflunisal and Fondaparinux 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.
Diflunisal belongs to Musculoskeletal; Fondaparinux belongs to Cardiovascular.
Why it happens
Additive hemostatic impairment: NSAID-induced platelet inhibition and mucosal injury combined with factor Xa-mediated anticoagulation.
What to do
Avoid the combination where possible and use paracetamol for analgesia instead. If it cannot be avoided, monitor for bleeding signs and hemoglobin and renal function.
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 Diflunisal
- Diflunisal + Ketorolac Contraindicated
- Diflunisal + Ketorolac intranasal Contraindicated
- Acemetacin + Diflunisal Major
- Acetazolamide + Diflunisal Major
- Alteplase + Diflunisal Major
- Amiloride + Diflunisal Major
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 Diflunisal with Fondaparinux?
MediHelp rates the interaction as major. Diflunisal and Fondaparinux 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. Diflunisal inhibits platelet function and can irritate the gastric mucosa, so adding it to fondaparinux raises the risk of bleeding, particularly gastrointestinal bleeding. The risk is greater in older patients and those with renal impairment, in whom fondaparinux accumulates.
How serious is the interaction between Diflunisal and Fondaparinux?
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 analgesia instead. If it cannot be avoided, monitor for bleeding signs and hemoglobin and renal function.
What other medicines interact with Diflunisal?
MediHelp also lists interactions of Diflunisal with, for example, Ketorolac, Ketorolac intranasal, Acemetacin. The full list is on the Diflunisal page.
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