Tazemetostat 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
Tazemetostat
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.
You've been prescribed tazemetostat (Tazverik) along with simvastatin (Zocor), a cholesterol medicine. Here's what to know: tazemetostat can speed up how your body breaks down simvastatin. That means less simvastatin stays in your system, so it may not lower your cholesterol as well as it should.
The good news is that this is manageable. Your care team can keep an eye on your cholesterol levels and adjust things if needed. Please don't stop or change either medicine on your own. Just bring this up with your pharmacist or doctor so they can make sure your cholesterol stays well controlled.
Effect: Tazemetostat induces CYP3A, reducing exposure of the CYP3A substrate simvastatin and potentially lowering its lipid-lowering efficacy.
- Mechanism: CYP3A enzyme induction by tazemetostat (simvastatin is extensively CYP3A4-metabolized).
- Magnitude: In a study, tazemetostat 800 mg BID reduced midazolam AUC by 40% and Cmax by 21%; a similar reduction is expected for simvastatin exposure.
- Direction: Reduced substrate effect (not a prodrug scenario).
- Evidence/onset: Probable; onset unspecified.
- Management: Monitor lipid panel; simvastatin dose may need individualized adjustment by the care team.
What happens
Reduced CYP3A substrate exposure and reduced efficacy of CYP3A substrate
Interaction Deep Dive
When tazemetostat is taken together with CYP3A substrates, the exposure to those substrates may fall, which can diminish their effectiveness. A drug interaction study in patients showed that giving tazemetostat 800 mg twice daily alongside oral midazolam (a sensitive CYP3A substrate) lowered the AUC of midazolam by 40% and its Cmax by 21%1.
Why it happens (mechanism)
Induction of CYP3A-substrate metabolism by tazemetostat
How to manage this interaction
This interaction can lower how well your simvastatin controls your cholesterol, but your care team can handle it.
- Keep taking both medicines exactly as prescribed unless your doctor tells you otherwise.
- Your team may check your cholesterol (lipid panel) more closely while you are on both drugs.
- Your simvastatin dose may need to be adjusted and individualized by your care team to keep it working well.
- Ask your pharmacist or prescriber whether your current statin plan still fits, especially if follow-up lab results show your cholesterol creeping up.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In a study of drug interactions, giving tazemetostat 800 mg twice daily together with oral midazolam (a sensitive CYP3A substrate) to patients reduced the AUC of midazolam by 40% and its Cmax by 21% 1.
Common questions
Can I take Tazemetostat and Simvastatin together?
Tazemetostat can make simvastatin work less effectively by speeding its breakdown, so your care team may monitor your cholesterol and adjust your statin dose. Keep taking both as prescribed and check in with your pharmacist or doctor. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Tazemetostat and Simvastatin interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Tazemetostat and Simvastatin interaction managed?
This interaction can lower how well your simvastatin controls your cholesterol, but your care team can handle it. Keep taking both medicines exactly as prescribed unless your doctor tells you otherwise. Your team may check your cholesterol (lipid panel) more closely while you are on both drugs. Your simvastatin dose may need to be adjusted and individualized by your care team to keep it working we… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Tazemetostat 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 a safer alternative to one of these medications for me?
References (1)
- Product Information: TAZVERIK(R) oral tablets, tazemetostat oral tablets. Epizyme Inc (per FDA), Cambridge, MA, 2024. DailyMed
Keep reading about Tazemetostat
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.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist