Drug interactions
Efavirenz + Progesterone micronized
Severity: Moderate
Efavirenz and Progesterone micronized: 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 lower circulating progesterone from oral micronized preparations. This may weaken endometrial protection in women taking estrogen, or reduce its other intended effects.
What this interaction means in plain words
Efavirenz and Progesterone micronized 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 breakthrough bleeding or loss of effect. Consider a higher progesterone dose or an alternative.
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 micronized?
MediHelp rates the interaction as moderate. Efavirenz and Progesterone micronized 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 lower circulating progesterone from oral micronized preparations. This may weaken endometrial protection in women taking estrogen, or reduce its other intended effects.
How serious is the interaction between Efavirenz and Progesterone micronized?
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 breakthrough bleeding or loss of effect. Consider a higher progesterone dose or an alternative.
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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