Drug interactions
Cobicistat + Ribociclib
Severity: Major
Cobicistat and Ribociclib: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Cobicistat is a strong CYP3A inhibitor and raises ribociclib exposure, increasing QT prolongation and neutropenia risk. Ribociclib may also modestly increase cobicistat levels.
What this interaction means in plain words
Cobicistat and Ribociclib can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Cobicistat belongs to Miscellaneous; Ribociclib belongs to Oncology.
Why it happens
Cobicistat inhibition of CYP3A4 reduces ribociclib clearance.
What to do
Avoid if possible; if needed, use the reduced ribociclib starting dose in the labeling and monitor ECG, electrolytes and blood counts.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Ribociclib
- Amiodarone + Ribociclib Contraindicated
- Cisapride + Ribociclib Contraindicated
- Dofetilide + Ribociclib Contraindicated
- Dronedarone + Ribociclib Contraindicated
- Flibanserin + Ribociclib Contraindicated
- Ibutilide + Ribociclib Contraindicated
Other interactions of Cobicistat
- Alfuzosin + Cobicistat Contraindicated
- Apalutamide + Cobicistat Contraindicated
- Cobicistat + Colchicine Contraindicated
- Cobicistat + Dronedarone Contraindicated
- Cobicistat + Eletriptan Contraindicated
- Cobicistat + Eplerenone Contraindicated
Frequently asked questions
Can I take Cobicistat with Ribociclib?
MediHelp rates the interaction as major. Cobicistat and Ribociclib can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Cobicistat is a strong CYP3A inhibitor and raises ribociclib exposure, increasing QT prolongation and neutropenia risk. Ribociclib may also modestly increase cobicistat levels.
How serious is the interaction between Cobicistat and Ribociclib?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible; if needed, use the reduced ribociclib starting dose in the labeling and monitor ECG, electrolytes and blood counts.
What other medicines interact with Ribociclib?
MediHelp also lists interactions of Ribociclib with, for example, Amiodarone, Cisapride, Dofetilide. The full list is on the Ribociclib page.
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