Drug interactions
Flecainide + Itraconazole
Severity: Major
Flecainide and Itraconazole: 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
Itraconazole may increase flecainide exposure and has negative inotropic effects, raising the risk of conduction slowing and proarrhythmia. Flecainide has a narrow therapeutic index and can cause serious ventricular arrhythmias.
What this interaction means in plain words
Flecainide and Itraconazole 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; Itraconazole belongs to Anti Fungals.
Why it happens
Itraconazole may inhibit CYP2D6/CYP3A4 metabolism of flecainide, with additive negative inotropic and conduction effects.
What to do
Avoid the combination where possible; otherwise monitor ECG (QRS and QT) and flecainide plasma levels, and reduce the dose if intervals prolong.
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 Itraconazole
- Alfuzosin + Itraconazole Contraindicated
- Alprazolam + Itraconazole Contraindicated
- Avanafil + Itraconazole Contraindicated
- Conivaptan + Itraconazole Contraindicated
- Dihydroergotamine intranasal + Itraconazole Contraindicated
- Dihydroergotamine + Itraconazole 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 Itraconazole?
MediHelp rates the interaction as major. Flecainide and Itraconazole 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. Itraconazole may increase flecainide exposure and has negative inotropic effects, raising the risk of conduction slowing and proarrhythmia. Flecainide has a narrow therapeutic index and can cause serious ventricular arrhythmias.
How serious is the interaction between Flecainide and Itraconazole?
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; otherwise monitor ECG (QRS and QT) and flecainide plasma levels, and reduce the dose if intervals prolong.
What other medicines interact with Itraconazole?
MediHelp also lists interactions of Itraconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Itraconazole page.
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