Drug interactions
Estrogens conjugated synthetic + Fondaparinux
Severity: Major
Estrogens conjugated synthetic 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
Synthetic conjugated estrogens increase the risk of venous thromboembolism and may oppose fondaparinux therapy. The concern is greatest in patients with active or recent clots.
What this interaction means in plain words
Estrogens conjugated synthetic 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-induced procoagulant changes versus factor Xa inhibition.
What to do
Avoid in active VTE and select a non-estrogen alternative where possible. Review thrombotic risk regularly if continued.
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 Estrogens conjugated synthetic with Fondaparinux?
MediHelp rates the interaction as major. Estrogens conjugated synthetic 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. Synthetic conjugated estrogens increase the risk of venous thromboembolism and may oppose fondaparinux therapy. The concern is greatest in patients with active or recent clots.
How serious is the interaction between Estrogens conjugated synthetic 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 in active VTE and select a non-estrogen alternative where possible. Review thrombotic risk regularly if continued.
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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