Drug interactions
Ethinyl estradiol-levonorgestrel + Fondaparinux
Severity: Moderate
Ethinyl estradiol-levonorgestrel and Fondaparinux: moderate 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
Fondaparinux is used to prevent or treat venous thromboembolism, whereas estrogen-containing contraceptives raise thromboembolic risk. The two do not interact pharmacokinetically, but the contraceptive's prothrombotic effect is a concern in patients who need anticoagulation.
What this interaction means in plain words
Ethinyl estradiol-levonorgestrel and Fondaparinux can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Ethinyl estradiol-levonorgestrel belongs to Endocrine; Fondaparinux belongs to Cardiovascular.
Why it happens
Pharmacodynamic opposition: estrogen increases clotting factor synthesis while fondaparinux inhibits factor Xa via antithrombin.
What to do
Review the need for an estrogen-containing contraceptive in patients with active or recent thrombosis and prefer progestin-only or non-hormonal methods. Continue fondaparinux as indicated.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Ethinyl estradiol-levonorgestrel
- Ethinyl estradiol-levonorgestrel + Fezolinetant Contraindicated
- Ethinyl estradiol-levonorgestrel + Ombitasvir / paritaprevir / ritonavir and dasabuvir Contraindicated
- Ethinyl estradiol-levonorgestrel + Tranexamic acid Contraindicated
- Aminocaproic acid + Ethinyl estradiol-levonorgestrel Major
- Amobarbital + Ethinyl estradiol-levonorgestrel Major
- Anastrozole + Ethinyl estradiol-levonorgestrel 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 Ethinyl estradiol-levonorgestrel with Fondaparinux?
MediHelp rates the interaction as moderate. Ethinyl estradiol-levonorgestrel and Fondaparinux can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Fondaparinux is used to prevent or treat venous thromboembolism, whereas estrogen-containing contraceptives raise thromboembolic risk. The two do not interact pharmacokinetically, but the contraceptive's prothrombotic effect is a concern in patients who need anticoagulation.
How serious is the interaction between Ethinyl estradiol-levonorgestrel and Fondaparinux?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Review the need for an estrogen-containing contraceptive in patients with active or recent thrombosis and prefer progestin-only or non-hormonal methods. Continue fondaparinux as indicated.
What other medicines interact with Ethinyl estradiol-levonorgestrel?
MediHelp also lists interactions of Ethinyl estradiol-levonorgestrel with, for example, Fezolinetant, Ombitasvir / paritaprevir / ritonavir and dasabuvir, Tranexamic acid. The full list is on the Ethinyl estradiol-levonorgestrel page.
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