Drug interactions
Lapatinib + Solifenacin
Severity: Moderate
Lapatinib and Solifenacin: 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 may increase solifenacin concentrations, and both drugs can prolong the QT interval. Together this may increase the risk of QT-related arrhythmia and antimuscarinic adverse effects.
What this interaction means in plain words
Lapatinib and Solifenacin 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; Solifenacin belongs to Genitourinary.
Why it happens
CYP3A4 inhibition by lapatinib plus additive QT prolongation.
What to do
Obtain a baseline ECG and check electrolytes, correcting any abnormalities. Limit solifenacin to the lower dose range and monitor for QT prolongation and anticholinergic effects.
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 Solifenacin
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 Solifenacin?
MediHelp rates the interaction as moderate. Lapatinib and Solifenacin 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 may increase solifenacin concentrations, and both drugs can prolong the QT interval. Together this may increase the risk of QT-related arrhythmia and antimuscarinic adverse effects.
How serious is the interaction between Lapatinib and Solifenacin?
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 check electrolytes, correcting any abnormalities. Limit solifenacin to the lower dose range and monitor for QT prolongation and anticholinergic effects.
What other medicines interact with Solifenacin?
MediHelp also lists interactions of Solifenacin with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Solifenacin page.
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