Drug interactions
Darunavir + Flecainide
Severity: Major
Darunavir and Flecainide: 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
Darunavir is usually given with ritonavir or cobicistat, both of which inhibit CYP2D6 and can markedly raise flecainide levels. This increases the risk of serious proarrhythmia and conduction block.
What this interaction means in plain words
Darunavir and Flecainide 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.
Darunavir belongs to Anti Virals; Flecainide belongs to Cardiovascular.
Why it happens
Boosted darunavir regimens inhibit CYP2D6 and CYP3A4 via the booster, decreasing flecainide metabolism.
What to do
Avoid or use with close ECG monitoring and flecainide dose reduction guided by levels. 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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Other interactions of Flecainide
- Flecainide + Nirmatrelvir Contraindicated
- Flecainide + Nirmatrelvir / ritonavir Contraindicated
- Flecainide + Pimozide Contraindicated
- Flecainide + Ritonavir Contraindicated
- Flecainide + Thioridazine Contraindicated
- Flecainide + Tipranavir Contraindicated
Other interactions of Darunavir
- Alfuzosin + Darunavir Contraindicated
- Avanafil + Darunavir Contraindicated
- Darunavir + Dronedarone Contraindicated
- Darunavir + Eletriptan Contraindicated
- Darunavir + Ergotamine Contraindicated
- Darunavir + Flibanserin Contraindicated
Frequently asked questions
Can I take Darunavir with Flecainide?
MediHelp rates the interaction as major. Darunavir and Flecainide 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. Darunavir is usually given with ritonavir or cobicistat, both of which inhibit CYP2D6 and can markedly raise flecainide levels. This increases the risk of serious proarrhythmia and conduction block.
How serious is the interaction between Darunavir and Flecainide?
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 or use with close ECG monitoring and flecainide dose reduction guided by levels. Consider an alternative antiarrhythmic.
What other medicines interact with Flecainide?
MediHelp also lists interactions of Flecainide with, for example, Nirmatrelvir, Nirmatrelvir / ritonavir, Pimozide. The full list is on the Flecainide page.
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