Drug interactions
Dacomitinib + Flecainide
Severity: Major
Dacomitinib 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
Dacomitinib strongly inhibits CYP2D6, which is a main route of flecainide metabolism. Flecainide levels may therefore rise, increasing the risk of conduction abnormalities and proarrhythmia because it has a narrow therapeutic index.
What this interaction means in plain words
Dacomitinib 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.
Dacomitinib belongs to Oncology; Flecainide belongs to Cardiovascular.
Why it happens
Dacomitinib inhibits CYP2D6, reducing flecainide clearance.
What to do
Avoid the combination where possible. If it cannot be avoided, monitor the ECG and flecainide plasma concentrations, and reduce the flecainide dose as needed.
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 Dacomitinib
- Dacomitinib + Thioridazine Contraindicated
- Amitriptyline + Dacomitinib Major
- Atomoxetine + Dacomitinib Major
- Brexpiprazole + Dacomitinib Major
- Clomipramine + Dacomitinib Major
- Dacomitinib + Desipramine Major
Frequently asked questions
Can I take Dacomitinib with Flecainide?
MediHelp rates the interaction as major. Dacomitinib 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. Dacomitinib strongly inhibits CYP2D6, which is a main route of flecainide metabolism. Flecainide levels may therefore rise, increasing the risk of conduction abnormalities and proarrhythmia because it has a narrow therapeutic index.
How serious is the interaction between Dacomitinib 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 the combination where possible. If it cannot be avoided, monitor the ECG and flecainide plasma concentrations, and reduce the flecainide dose as needed.
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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