Etravirine and Simvastatin: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 4, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Etravirine
Simvastatin
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
Here's what's going on. Etravirine (Intelence) is an HIV medicine that can speed up the liver enzyme that breaks down your cholesterol drug, simvastatin (Zocor). When simvastatin is cleared faster, less of it stays in your blood, so it may not lower your cholesterol as well as it should.
The good news is this is based mostly on how these drugs work in theory, not on lots of real-world cases. Don't change anything on your own. Your care team can keep an eye on your cholesterol numbers and adjust your simvastatin dose if needed. Just make sure both your pharmacist and doctor know you take both.
Effect: Etravirine may induce CYP3A4-mediated metabolism of simvastatin, decreasing simvastatin plasma concentrations and potentially reducing its lipid-lowering efficacy.
- Direction: Enzyme induction, reduced simvastatin exposure (AUC/Cmax). Simvastatin is metabolized to its active acid, but net effect here is loss of efficacy from lower parent/active levels.
- Evidence: Theoretical; magnitude not quantified.
- Onset: Unspecified (induction is typically delayed, days to weeks).
- Management: Monitor lipid panel for attenuated response; simvastatin dose may be individualized/uptitrated by the care team if efficacy is reduced.
What happens
Decreased simvastatin plasma concentrations
Interaction Deep Dive
Taking etravirine together with simvastatin can lower the plasma levels of simvastatin, an effect attributable to induction of simvastatin metabolism via CYP3A4. It may be necessary to adjust the simvastatin dose1. Watching the patient for diminished simvastatin effectiveness could be advisable.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism of simvastatin by etravirine
How to manage this interaction
Keep taking both medicines as prescribed unless your prescriber tells you otherwise. This interaction is manageable.
- Your care team may check your cholesterol (lipid panel) to make sure your simvastatin is still working while you are on etravirine.
- If your cholesterol is not controlled as expected, your simvastatin dose may need to be adjusted and individualized by your care team.
- Tell your pharmacist and doctor that you take both drugs, and report any concerns at your follow-up visits.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Etravirine and Simvastatin together?
Etravirine may lower simvastatin levels and make it work less well on your cholesterol, so your team may monitor your lipids and adjust the simvastatin dose if needed. Keep taking both as prescribed and let your pharmacist or doctor know you use both. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Etravirine and Simvastatin interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Etravirine and Simvastatin interaction managed?
Keep taking both medicines as prescribed unless your prescriber tells you otherwise. This interaction is manageable. Your care team may check your cholesterol (lipid panel) to make sure your simvastatin is still working while you are on etravirine. If your cholesterol is not controlled as expected, your simvastatin dose may need to be adjusted and individualized by your care team. Tell your pharma… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Etravirine or Simvastatin need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (1)
- Product Information: INTELENCE(TM) oral tablets, etravirine oral tablets. Tibotec Therapeutics,Inc, Raritan, NJ, 2008. DailyMed
Keep reading about Etravirine
Keep reading about Simvastatin
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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