Drug interactions
Lapatinib + Trifluoperazine
Severity: Moderate
Lapatinib and Trifluoperazine: 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 lapatinib and the phenothiazine trifluoperazine can prolong the QT interval. Combined use increases the risk of torsades de pointes, particularly with electrolyte abnormalities or structural heart disease.
What this interaction means in plain words
Lapatinib and Trifluoperazine 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 pharmacodynamic QT prolongation.
What to do
Check a baseline ECG and electrolytes, and monitor the QTc periodically. Replace one agent if the QTc becomes markedly 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 Trifluoperazine?
MediHelp rates the interaction as moderate. Lapatinib and Trifluoperazine 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 lapatinib and the phenothiazine trifluoperazine can prolong the QT interval. Combined use increases the risk of torsades de pointes, particularly with electrolyte abnormalities or structural heart disease.
How serious is the interaction between Lapatinib and Trifluoperazine?
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 the QTc periodically. Replace one agent if the QTc becomes markedly 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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