Dronabinol and Mavacamten: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Mavacamten
Dronabinol
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.
What happens
Reduced CYP2C9 substrate exposure and reduced efficacy of CYP2C9 substrate
Interaction Deep Dive
Concomitant use of mavacamten with CYP2C9 substrates may reduce CYP2C9 substrates exposure which may also reduce efficacy of CYP2C9 substrates. Hence, closely monitor when mavacamten is used in combination with CYP2C9 substrates. In a drug interaction study, concomitant use of mavacamten once daily in hypertrophic cardiomyopathy patients is predicted to decrease AUC and Cmax of TOLBUTamide, a CYP2C9 substrate, by 54% and by 23%, respectively, depending on the dose of mavacamten and CYP2C19 phenotype1.
Why it happens (mechanism)
Induction of CYP2C9 substrate metabolism by mavacamten
Literature reports
1 report — tap to read
a) In a drug interaction study, concomitant use of mavacamten once daily in hypertrophic cardiomyopathy patients is predicted to decrease AUC and Cmax of TOLBUTamide, a CYP2C9 substrate, by 54% and by 23%, respectively, depending on the dose of mavacamten and CYP2C19 phenotype 1.
Common questions
Can I take Dronabinol and Mavacamten together?
Reduced CYP2C9 substrate exposure and reduced efficacy of CYP2C9 substrate Always confirm with your pharmacist or prescriber before making any change.
How serious is the Dronabinol and Mavacamten 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 strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Dronabinol or Mavacamten 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 Dronabinol
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