Mavacamten 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
Mavacamten
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. Mavacamten (Camzyos) can gently speed up the enzyme in your liver that breaks down simvastatin (Zocor). When that enzyme works faster, your body may clear the simvastatin a little quicker, which could leave less of it in your system to lower your cholesterol.
The good news is that this is based on theory and small studies, and the effect looks modest. Your care team can keep an eye on your cholesterol numbers and adjust things if needed. Please keep taking both medicines exactly as prescribed, and just mention this to your pharmacist or doctor so they can watch for any change.
Mechanism: Mavacamten is a weak CYP3A4 inducer; simvastatin is a CYP3A4 substrate. Induction may increase simvastatin metabolism, lowering exposure (AUC/Cmax) and potentially reducing lipid-lowering efficacy.
- Direction: reduced simvastatin effect (neither drug is a prodrug here).
- Magnitude: extrapolated from midazolam probe; AUC decreased ~13% (up to ~45% at upper therapeutic mavacamten range).
- Onset: unspecified; induction is typically delayed.
- Evidence: theoretical/predicted.
- Management: monitor lipid panel; dose may be individualized by the care team if response wanes.
What happens
Reduced CYP3A4 substrate exposure and reduced efficacy of CYP3A4 substrate
Interaction Deep Dive
When mavacamten is given together with CYP3A4 substrates, the exposure of those substrates may fall, potentially lowering their effectiveness as well. For this reason, careful monitoring is warranted whenever mavacamten is used alongside CYP3A4 substrates. A drug interaction study in healthy subjects showed that a 16 day regimen of mavacamten (25 mg on days 1 and 2, then 15 mg for 14 days) lowered midazolam AUC(inf) by 13% and Cmax by 7%. In symptomatic obstructive hypertrophic cardiomyopathy (HCM) patients receiving once daily mavacamten at the upper end of the therapeutic range, midazolam AUC(inf) and Cmax are projected to fall by as much as 45% and 24%, respectively1.
Why it happens (mechanism)
Induction of CYP3A4-substrate metabolism by mavacamten
How to manage this interaction
This is manageable. The concern is that mavacamten may lower simvastatin levels a bit, which could reduce its cholesterol-lowering effect. Because this is theoretical and appears modest, no fixed change is required.
- Keep taking both medications exactly as prescribed.
- Your care team may check your cholesterol (lipid panel) more closely to confirm simvastatin is still working.
- Your simvastatin dose may need to be adjusted and individualized by your care team based on those results.
- Ask your pharmacist or doctor before making any change, and report if your numbers drift.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In a drug interaction study, the concurrent administration of a 16 day regimen of mavacamten (25 mg on days 1 and 2, followed by 15 mg for 14 days) reduced the AUC(inf) and Cmax of midazolam by 13% and 7%, respectively, in healthy subjects. When mavacamten is given once daily at the upper end of the therapeutic range in symptomatic obstructive hypertrophic cardiomyopathy (HCM) patients, midazolam AUC(inf) and Cmax are projected to fall by as much as 45% and 24%, respectively 1.
Common questions
Can I take Mavacamten and Simvastatin together?
Mavacamten may slightly speed up how your body clears simvastatin, which could make it a little less effective at lowering cholesterol. Keep taking both as prescribed and let your care team monitor your lipid levels. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Mavacamten 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 Mavacamten and Simvastatin interaction managed?
This is manageable. The concern is that mavacamten may lower simvastatin levels a bit, which could reduce its cholesterol-lowering effect. Because this is theoretical and appears modest, no fixed change is required. Keep taking both medications exactly as prescribed. Your care team may check your cholesterol (lipid panel) more closely to confirm simvastatin is still working. Your simvastatin dose… 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 Mavacamten 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: CAMZYOS(R) oral capsules, mavacamten oral capsules. Bristol-Myers Squibb Company (per Manufacturer), Princeton, NJ, 2025. DailyMed
Keep reading about Mavacamten
Keep reading about Simvastatin
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major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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