Drug interactions
Granisetron + Lapatinib
Severity: Moderate
Granisetron 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 granisetron may add to this effect. The combination may raise the risk of ventricular arrhythmia, particularly with electrolyte disturbances.
What this interaction means in plain words
Granisetron 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.
Granisetron belongs to Gastrointestinal Tract; Lapatinib belongs to Oncology.
Why it happens
Additive QT prolongation; lapatinib also inhibits CYP3A4 and may modestly raise granisetron levels.
What to do
Obtain a baseline ECG and correct potassium and magnesium before starting. Repeat the ECG periodically and consider an alternative antiemetic if the QTc lengthens.
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 Granisetron
- Apomorphine + Granisetron Contraindicated
- Amiodarone + Granisetron Major
- Amisulpride + Granisetron Major
- Arsenic trioxide + Granisetron Major
- Artemether / lumefantrine + Granisetron Major
- Artemether + Granisetron Major
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 Granisetron with Lapatinib?
MediHelp rates the interaction as moderate. Granisetron 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 granisetron may add to this effect. The combination may raise the risk of ventricular arrhythmia, particularly with electrolyte disturbances.
How serious is the interaction between Granisetron 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: Obtain a baseline ECG and correct potassium and magnesium before starting. Repeat the ECG periodically and consider an alternative antiemetic if the QTc lengthens.
What other medicines interact with Granisetron?
MediHelp also lists interactions of Granisetron with, for example, Apomorphine, Amiodarone, Amisulpride. The full list is on the Granisetron page.
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