Drug interactions
Antithrombin alfa + Ethinyl estradiol-levonorgestrel
Severity: Major
Antithrombin alfa and Ethinyl estradiol-levonorgestrel: 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
Combined hormonal contraceptives increase thrombotic risk, which opposes the intended antithrombotic effect of antithrombin. In patients with antithrombin deficiency, estrogen-containing products add substantially to thrombosis risk.
What this interaction means in plain words
Antithrombin alfa and Ethinyl estradiol-levonorgestrel 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
Estrogen raises procoagulant factors and lowers antithrombin and protein S activity, pharmacodynamically opposing antithrombin replacement.
What to do
Avoid estrogen-containing contraceptives in patients with antithrombin deficiency; use a progestin-only or non-hormonal method. Monitor antithrombin activity and coagulation status.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Antithrombin alfa and Ethinyl estradiol-levonorgestrel, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
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
Frequently asked questions
Can I take Antithrombin alfa with Ethinyl estradiol-levonorgestrel?
MediHelp rates the interaction as major. Antithrombin alfa and Ethinyl estradiol-levonorgestrel 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. Combined hormonal contraceptives increase thrombotic risk, which opposes the intended antithrombotic effect of antithrombin. In patients with antithrombin deficiency, estrogen-containing products add substantially to thrombosis risk.
How serious is the interaction between Antithrombin alfa and Ethinyl estradiol-levonorgestrel?
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-containing contraceptives in patients with antithrombin deficiency; use a progestin-only or non-hormonal method. Monitor antithrombin activity and coagulation status.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
