Drug interactions
Conjugated estrogens + Fondaparinux
Severity: Major
Conjugated estrogens and Fondaparinux: 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
Conjugated estrogens raise thromboembolic risk and can counteract the protective purpose of fondaparinux. This is most relevant in patients being treated for an existing clot.
What this interaction means in plain words
Conjugated estrogens 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.
Why it happens
Pharmacodynamic opposition: estrogen-mediated prothrombotic effects versus factor Xa inhibition.
What to do
Avoid estrogen therapy in active thrombosis and use a non-hormonal alternative. Reassess VTE risk if therapy continues.
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 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 Conjugated estrogens with Fondaparinux?
MediHelp rates the interaction as major. Conjugated estrogens 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. Conjugated estrogens raise thromboembolic risk and can counteract the protective purpose of fondaparinux. This is most relevant in patients being treated for an existing clot.
How serious is the interaction between Conjugated estrogens 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 estrogen therapy in active thrombosis and use a non-hormonal alternative. Reassess VTE risk if therapy continues.
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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