Drug interactions
Ketoconazole + Propafenone
Severity: Major
Ketoconazole and Propafenone: major interaction.
Last updated
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
Ketoconazole can raise propafenone concentrations, increasing the risk of proarrhythmia, QRS and QT prolongation, and CNS or beta-blocking effects. The risk is greatest in poor CYP2D6 metabolizers or with CYP2D6 inhibitors.
What this interaction means in plain words
Ketoconazole 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.
Ketoconazole belongs to Anti Fungals; Propafenone belongs to Cardiovascular.
Why it happens
Ketoconazole inhibits CYP3A4, a pathway of propafenone metabolism, and its effect is amplified when CYP2D6 is impaired.
What to do
Avoid the combination where possible; if needed, monitor the ECG and reduce the propafenone dose. Be especially cautious in poor CYP2D6 metabolizers.
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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Other interactions of Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
Other interactions of Propafenone
- Dofetilide + Propafenone Contraindicated
- Dronedarone + Propafenone Contraindicated
- Nilotinib + Propafenone Contraindicated
- Nirmatrelvir / ritonavir + Propafenone Contraindicated
- Nirmatrelvir + Propafenone Contraindicated
- Pimozide + Propafenone Contraindicated
Frequently asked questions
Can I take Ketoconazole with Propafenone?
MediHelp rates the interaction as major. Ketoconazole 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. Ketoconazole can raise propafenone concentrations, increasing the risk of proarrhythmia, QRS and QT prolongation, and CNS or beta-blocking effects. The risk is greatest in poor CYP2D6 metabolizers or with CYP2D6 inhibitors.
How serious is the interaction between Ketoconazole 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; if needed, monitor the ECG and reduce the propafenone dose. Be especially cautious in poor CYP2D6 metabolizers.
What other medicines interact with Ketoconazole?
MediHelp also lists interactions of Ketoconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Ketoconazole page.
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