Drug interactions
Lapatinib + Propafenone
Severity: Moderate
Lapatinib and Propafenone: 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 inhibits CYP3A4 and can prolong the QT interval. Propafenone exposure may increase, and the combined effects on repolarization and conduction raise the risk of arrhythmia.
What this interaction means in plain words
Lapatinib and Propafenone 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 belongs to Oncology; Propafenone belongs to Cardiovascular.
Why it happens
Lapatinib inhibition of CYP3A4 metabolism of propafenone plus additive QT prolongation.
What to do
Obtain a baseline ECG and monitor ECG and electrolytes during co-therapy. Reduce propafenone dose if conduction intervals lengthen.
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?
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Other interactions of Propafenone
- Dofetilide + Propafenone Contraindicated
- Dronedarone + Propafenone Contraindicated
- Nilotinib + Propafenone Contraindicated
- Nirmatrelvir / ritonavir + Propafenone Contraindicated
- Nirmatrelvir + Propafenone Contraindicated
- Pimozide + Propafenone 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 Lapatinib with Propafenone?
MediHelp rates the interaction as moderate. Lapatinib and Propafenone 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 inhibits CYP3A4 and can prolong the QT interval. Propafenone exposure may increase, and the combined effects on repolarization and conduction raise the risk of arrhythmia.
How serious is the interaction between Lapatinib and Propafenone?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain a baseline ECG and monitor ECG and electrolytes during co-therapy. Reduce propafenone dose if conduction intervals lengthen.
What other medicines interact with Propafenone?
MediHelp also lists interactions of Propafenone with, for example, Dofetilide, Dronedarone, Nilotinib. The full list is on the Propafenone page.
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