Drug interactions
Lapatinib + Promazine
Severity: Moderate
Lapatinib and Promazine: 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
Both agents may prolong the QT interval, which can raise the risk of torsades de pointes, especially with electrolyte disturbances or heart disease.
What this interaction means in plain words
Lapatinib and Promazine 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.
Why it happens
Additive QT prolongation via cardiac potassium channel blockade.
What to do
Check a baseline ECG and electrolytes and monitor QTc during co-therapy. Choose an alternative with less QT effect if QTc becomes prolonged.
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 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 Promazine?
MediHelp rates the interaction as moderate. Lapatinib and Promazine 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. Both agents may prolong the QT interval, which can raise the risk of torsades de pointes, especially with electrolyte disturbances or heart disease.
How serious is the interaction between Lapatinib and Promazine?
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 a baseline ECG and electrolytes and monitor QTc during co-therapy. Choose an alternative with less QT effect if QTc becomes prolonged.
What other medicines interact with Lapatinib?
MediHelp also lists interactions of Lapatinib with, for example, Dofetilide, Ibutilide, Pimozide. The full list is on the Lapatinib page.
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