Drug interactions
Ethinylestradiol + Mifepristone
Severity: Moderate
Ethinylestradiol and Mifepristone: 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
Mifepristone inhibits CYP3A4, which contributes to ethinylestradiol metabolism, so estrogen exposure may increase. In addition, mifepristone's antiprogestogen and antiglucocorticoid activity may reduce the effect of hormonal contraception. Estrogen-related adverse effects may be more likely.
What this interaction means in plain words
Ethinylestradiol and Mifepristone 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.
Why it happens
Mifepristone inhibits CYP3A4 and antagonizes progesterone receptors, altering estrogen exposure and contraceptive effect.
What to do
Monitor for estrogen-related adverse effects and consider adding a non-hormonal contraceptive method. Review the need for combined hormonal products in patients on chronic mifepristone.
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 Mifepristone
- Apixaban + Mifepristone Contraindicated
- Argatroban + Mifepristone Contraindicated
- Cisapride + Mifepristone Contraindicated
- Cortisone + Mifepristone Contraindicated
- Cyclosporin + Mifepristone Contraindicated
- Dabigatran etexilate + Mifepristone Contraindicated
Frequently asked questions
Can I take Ethinylestradiol with Mifepristone?
MediHelp rates the interaction as moderate. Ethinylestradiol and Mifepristone 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. Mifepristone inhibits CYP3A4, which contributes to ethinylestradiol metabolism, so estrogen exposure may increase. In addition, mifepristone's antiprogestogen and antiglucocorticoid activity may reduce the effect of hormonal contraception. Estrogen-related adverse effects may be more likely.
How serious is the interaction between Ethinylestradiol and Mifepristone?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for estrogen-related adverse effects and consider adding a non-hormonal contraceptive method. Review the need for combined hormonal products in patients on chronic mifepristone.
What other medicines interact with Mifepristone?
MediHelp also lists interactions of Mifepristone with, for example, Apixaban, Argatroban, Cisapride. The full list is on the Mifepristone page.
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