Drug interactions
Efavirenz + Progesterone intravaginal
Severity: Moderate
Efavirenz and Progesterone intravaginal: 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 induces CYP3A4 and may speed the metabolism of progesterone, lowering systemic levels. This could reduce the effect of progesterone used for luteal support or endometrial protection, although the local vaginal effect may be preserved.
What this interaction means in plain words
Efavirenz and Progesterone intravaginal 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
Efavirenz induces CYP3A4, increasing progesterone metabolism.
What to do
Monitor for reduced efficacy, such as breakthrough bleeding or failed luteal support. Consider adjusting the progesterone dose.
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
Frequently asked questions
Can I take Efavirenz with Progesterone intravaginal?
MediHelp rates the interaction as moderate. Efavirenz and Progesterone intravaginal 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 induces CYP3A4 and may speed the metabolism of progesterone, lowering systemic levels. This could reduce the effect of progesterone used for luteal support or endometrial protection, although the local vaginal effect may be preserved.
How serious is the interaction between Efavirenz and Progesterone intravaginal?
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 reduced efficacy, such as breakthrough bleeding or failed luteal support. Consider adjusting the progesterone dose.
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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