Drug interactions
Lapatinib + Zonisamide
Severity: Minor
Lapatinib and Zonisamide: minor 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 is a CYP3A4 inhibitor and may raise zonisamide concentrations. Dose-related adverse effects such as somnolence, dizziness or confusion could become more likely.
What this interaction means in plain words
Lapatinib and Zonisamide have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Lapatinib belongs to Oncology; Zonisamide belongs to Central Nervous System.
Why it happens
Inhibition of CYP3A4-mediated zonisamide metabolism by lapatinib.
What to do
Monitor for zonisamide toxicity when lapatinib is started. Reduce the zonisamide dose if adverse effects occur.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Zonisamide
- Zonisamide + Zuranolone Major
- Acetazolamide + Zonisamide Moderate
- Amisulpride + Zonisamide Moderate
- Amobarbital + Zonisamide Moderate
- Apalutamide + Zonisamide Moderate
- Asenapine transdermal + Zonisamide Moderate
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 Zonisamide?
MediHelp rates the interaction as minor. Lapatinib and Zonisamide have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Lapatinib is a CYP3A4 inhibitor and may raise zonisamide concentrations. Dose-related adverse effects such as somnolence, dizziness or confusion could become more likely.
How serious is the interaction between Lapatinib and Zonisamide?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for zonisamide toxicity when lapatinib is started. Reduce the zonisamide dose if adverse effects occur.
What other medicines interact with Zonisamide?
MediHelp also lists interactions of Zonisamide with, for example, Zuranolone, Acetazolamide, Amisulpride. The full list is on the Zonisamide page.
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