Drug interactions
Flecainide + Lapatinib
Severity: Moderate
Flecainide and Lapatinib: moderate 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
Lapatinib can prolong the QT interval and flecainide affects cardiac conduction and carries proarrhythmic risk. Using them together may raise the likelihood of serious ventricular arrhythmias, particularly with electrolyte disturbance or structural heart disease.
What this interaction means in plain words
Flecainide and Lapatinib can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Flecainide belongs to Cardiovascular; Lapatinib belongs to Oncology.
Why it happens
Additive pharmacodynamic effects on cardiac repolarization and conduction.
What to do
Check baseline and follow-up ECGs and correct hypokalemia and hypomagnesemia. Consider an alternative if QTc rises significantly.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Flecainide and Lapatinib, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
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 Lapatinib
- Dofetilide + Lapatinib Contraindicated
- Ibutilide + Lapatinib Contraindicated
- Lapatinib + Pimozide Contraindicated
- Lapatinib + Saquinavir Contraindicated
- Lapatinib + Thioridazine Contraindicated
- Adagrasib + Lapatinib Major
Frequently asked questions
Can I take Flecainide with Lapatinib?
MediHelp rates the interaction as moderate. Flecainide and Lapatinib can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Lapatinib can prolong the QT interval and flecainide affects cardiac conduction and carries proarrhythmic risk. Using them together may raise the likelihood of serious ventricular arrhythmias, particularly with electrolyte disturbance or structural heart disease.
How serious is the interaction between Flecainide and Lapatinib?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check baseline and follow-up ECGs and correct hypokalemia and hypomagnesemia. Consider an alternative if QTc rises significantly.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
