Drug interactions
Flecainide + Posaconazole
Severity: Major
Flecainide and Posaconazole: 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
Flecainide slows cardiac conduction and can prolong QT, and posaconazole adds QT prolongation, raising the risk of ventricular arrhythmias. Flecainide has a narrow therapeutic index and proarrhythmic potential in structural heart disease.
What this interaction means in plain words
Flecainide and Posaconazole 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.
Flecainide belongs to Cardiovascular; Posaconazole belongs to Anti Fungals.
Why it happens
Additive effects on cardiac repolarization and conduction.
What to do
Avoid the combination when possible; if it is necessary, monitor ECG (QRS and QTc), electrolytes and flecainide concentrations.
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 Posaconazole
- Artemether + Posaconazole Contraindicated
- Avanafil + Posaconazole Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Conivaptan + Posaconazole Contraindicated
- Dihydroergotamine intranasal + Posaconazole Contraindicated
- Dihydroergotamine + Posaconazole Contraindicated
Other interactions of Flecainide
- Flecainide + Nirmatrelvir Contraindicated
- Flecainide + Nirmatrelvir / ritonavir Contraindicated
- Flecainide + Pimozide Contraindicated
- Flecainide + Ritonavir Contraindicated
- Flecainide + Thioridazine Contraindicated
- Flecainide + Tipranavir Contraindicated
Frequently asked questions
Can I take Flecainide with Posaconazole?
MediHelp rates the interaction as major. Flecainide and Posaconazole 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. Flecainide slows cardiac conduction and can prolong QT, and posaconazole adds QT prolongation, raising the risk of ventricular arrhythmias. Flecainide has a narrow therapeutic index and proarrhythmic potential in structural heart disease.
How serious is the interaction between Flecainide and Posaconazole?
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 when possible; if it is necessary, monitor ECG (QRS and QTc), electrolytes and flecainide concentrations.
What other medicines interact with Posaconazole?
MediHelp also lists interactions of Posaconazole with, for example, Artemether, Avanafil, Cobimetinib. The full list is on the Posaconazole page.
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