Drug interactions
Ethinylestradiol + Ketoconazole
Severity: Moderate
Ethinylestradiol and Ketoconazole: 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
Ketoconazole can raise ethinylestradiol concentrations, potentially increasing estrogenic adverse effects such as nausea, breast tenderness and breakthrough bleeding. Contraceptive efficacy is not expected to fall.
What this interaction means in plain words
Ethinylestradiol and Ketoconazole 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
Ketoconazole inhibits CYP3A4, which contributes to ethinylestradiol oxidative metabolism.
What to do
Monitor for estrogen-related adverse effects and bleeding changes. Consider an alternative antifungal or lower-dose estrogen if they are troublesome.
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 Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
Frequently asked questions
Can I take Ethinylestradiol with Ketoconazole?
MediHelp rates the interaction as moderate. Ethinylestradiol and Ketoconazole 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. Ketoconazole can raise ethinylestradiol concentrations, potentially increasing estrogenic adverse effects such as nausea, breast tenderness and breakthrough bleeding. Contraceptive efficacy is not expected to fall.
How serious is the interaction between Ethinylestradiol and Ketoconazole?
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 bleeding changes. Consider an alternative antifungal or lower-dose estrogen if they are troublesome.
What other medicines interact with Ketoconazole?
MediHelp also lists interactions of Ketoconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Ketoconazole page.
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