Cobimetinib and Dronedarone: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Dronedarone
Cobimetinib
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
Increased cobimetinib plasma concentrations
Interaction Deep Dive
Avoid concomitant use of cobimetinib (a CYP3A substrate) with moderate CYP3A inhibitors, as coadministration may result in increased cobimetinib plasma concentrations. If short-term (14 days or less) administration of moderate CYP3A inhibitors is necessary in patients taking cobimetinib 60 mg, reduce the cobimetinib dose to 20 mg. After discontinuing the moderate CYP3A inhibitor, resume cobimetinib at the previous dose. In patients already taking a reduced cobimetinib dose (ie, 40 or 20 mg/day), use an alternative to the CYP3A inhibitor1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of cobimetinib
Literature reports
1 report — tap to read
a) Simulated concurrent use of cobimetinib at a reduced dose of 20 mg with short-term (less than 14 days) treatment of a moderate CYP3A inhibitor showed that predicted cobimetinib steady-state concentrations were similar to observed steady-state concentrations of cobimetinib 60 mg alone 1.
Common questions
Can I take Cobimetinib and Dronedarone together?
Increased cobimetinib plasma concentrations Always confirm with your pharmacist or prescriber before making any change.
How serious is the Cobimetinib and Dronedarone 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 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 Cobimetinib or Dronedarone 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: COTELLIC(TM) oral tablets, cobimetinib oral tablets. Genentech USA, Inc.(per FDA), South San Francisco, CA, 2015. DailyMed
Keep reading about Dronedarone
Keep reading about Cobimetinib
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