Drug interactions
Estradiol + Fostemsavir
Severity: Moderate
Estradiol and Fostemsavir: 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
Fostemsavir's active metabolite temsavir increases ethinyl estradiol exposure. Higher estrogen levels raise the risk of estrogen-related adverse effects, especially thromboembolism in predisposed patients.
What this interaction means in plain words
Estradiol and Fostemsavir 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.
Estradiol belongs to Endocrine; Fostemsavir belongs to Anti Virals.
Why it happens
Temsavir inhibits metabolism or transport of estrogens, increasing exposure; the mechanism is not fully defined.
What to do
Limit ethinyl estradiol to 30 mcg daily in combination products and assess thromboembolic risk factors. Consider non-estrogen contraception or lower-dose options in high-risk patients.
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 Fostemsavir
- Apalutamide + Fostemsavir Contraindicated
- Carbamazepine + Fostemsavir Contraindicated
- Enzalutamide + Fostemsavir Contraindicated
- Fostemsavir + Mitotane Contraindicated
- Fostemsavir + Phenytoin Contraindicated
- Fostemsavir + Rifampicin Contraindicated
Other interactions of Estradiol
- Anastrozole + Estradiol Contraindicated
- Estradiol + Fezolinetant Contraindicated
- Estradiol + Ospemifene Contraindicated
- Antithrombin alfa + Estradiol Major
- Antithrombin iii + Estradiol Major
- Estradiol + Exemestane Major
Frequently asked questions
Can I take Estradiol with Fostemsavir?
MediHelp rates the interaction as moderate. Estradiol and Fostemsavir 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. Fostemsavir's active metabolite temsavir increases ethinyl estradiol exposure. Higher estrogen levels raise the risk of estrogen-related adverse effects, especially thromboembolism in predisposed patients.
How serious is the interaction between Estradiol and Fostemsavir?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Limit ethinyl estradiol to 30 mcg daily in combination products and assess thromboembolic risk factors. Consider non-estrogen contraception or lower-dose options in high-risk patients.
What other medicines interact with Fostemsavir?
MediHelp also lists interactions of Fostemsavir with, for example, Apalutamide, Carbamazepine, Enzalutamide. The full list is on the Fostemsavir page.
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