Drug interactions
Efavirenz + Estradiol
Severity: Moderate
Efavirenz and Estradiol: 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
Efavirenz may lower estradiol exposure by inducing its metabolism, possibly causing recurrence of menopausal symptoms or reduced hormone effect.
What this interaction means in plain words
Efavirenz and Estradiol 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.
Efavirenz belongs to Anti Virals; Estradiol belongs to Endocrine.
Why it happens
Efavirenz induces CYP3A4, increasing estradiol clearance.
What to do
Monitor symptom control and consider adjusting the estradiol dose. For contraception, use a reliable additional or alternative method.
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 Efavirenz
- Cobimetinib + Efavirenz Contraindicated
- Dienogest / estradiol valerate + Efavirenz Contraindicated
- Dihydroergotamine intranasal + Efavirenz Contraindicated
- Dihydroergotamine + Efavirenz Contraindicated
- Doravirine + Efavirenz Contraindicated
- Efavirenz + Elbasvir / grazoprevir 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 Efavirenz with Estradiol?
MediHelp rates the interaction as moderate. Efavirenz and Estradiol 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. Efavirenz may lower estradiol exposure by inducing its metabolism, possibly causing recurrence of menopausal symptoms or reduced hormone effect.
How serious is the interaction between Efavirenz and Estradiol?
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 symptom control and consider adjusting the estradiol dose. For contraception, use a reliable additional or alternative method.
What other medicines interact with Efavirenz?
MediHelp also lists interactions of Efavirenz with, for example, Cobimetinib, Dienogest / estradiol valerate, Dihydroergotamine intranasal. The full list is on the Efavirenz page.
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