Drug interactions
Cobicistat + Propafenone
Severity: Major
Cobicistat and Propafenone: 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 CYP3A4 inhibitor and also inhibits CYP2D6, so it can substantially increase propafenone exposure. This raises the risk of conduction disturbances, bradycardia and ventricular arrhythmias.
What this interaction means in plain words
Cobicistat and Propafenone 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; Propafenone belongs to Cardiovascular.
Why it happens
Inhibition of CYP3A4 and CYP2D6 by cobicistat reduces propafenone clearance.
What to do
Avoid the combination where possible, or use a reduced propafenone dose with ECG monitoring of PR and QRS intervals. Consider an alternative antiarrhythmic.
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 Propafenone
- Dofetilide + Propafenone Contraindicated
- Dronedarone + Propafenone Contraindicated
- Nilotinib + Propafenone Contraindicated
- Nirmatrelvir / ritonavir + Propafenone Contraindicated
- Nirmatrelvir + Propafenone Contraindicated
- Pimozide + Propafenone 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 Propafenone?
MediHelp rates the interaction as major. Cobicistat and Propafenone 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 CYP3A4 inhibitor and also inhibits CYP2D6, so it can substantially increase propafenone exposure. This raises the risk of conduction disturbances, bradycardia and ventricular arrhythmias.
How serious is the interaction between Cobicistat and Propafenone?
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 the combination where possible, or use a reduced propafenone dose with ECG monitoring of PR and QRS intervals. Consider an alternative antiarrhythmic.
What other medicines interact with Propafenone?
MediHelp also lists interactions of Propafenone with, for example, Dofetilide, Dronedarone, Nilotinib. The full list is on the Propafenone page.
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