Drug interactions
Lapatinib + Topotecan
Severity: Major
Lapatinib and Topotecan: major 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 P-gp and BCRP, which can increase topotecan absorption and reduce its elimination. This may worsen myelosuppression and gastrointestinal toxicity, and the effect is most relevant for oral topotecan.
What this interaction means in plain words
Lapatinib and Topotecan can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Lapatinib belongs to Oncology; Topotecan belongs to Oncology.
Why it happens
Lapatinib inhibits the P-gp and BCRP efflux transporters involved in topotecan absorption and elimination.
What to do
Avoid combining with oral topotecan. If used with intravenous topotecan, monitor blood counts closely and reduce the topotecan dose if toxicity occurs.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Lapatinib and Topotecan, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
Other interactions of Lapatinib
- Dofetilide + Lapatinib Contraindicated
- Ibutilide + Lapatinib Contraindicated
- Lapatinib + Pimozide Contraindicated
- Lapatinib + Saquinavir Contraindicated
- Lapatinib + Thioridazine Contraindicated
- Adagrasib + Lapatinib Major
Other interactions of Topotecan
- Adenovirus types 4 and 7 live + Topotecan Contraindicated
- Amiodarone + Topotecan Major
- Cisplatin + Topotecan Major
- Cobicistat + Topotecan Major
- Cyclosporine + Topotecan Major
- Cyclosporin + Topotecan Major
Frequently asked questions
Can I take Lapatinib with Topotecan?
MediHelp rates the interaction as major. Lapatinib and Topotecan can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Lapatinib inhibits P-gp and BCRP, which can increase topotecan absorption and reduce its elimination. This may worsen myelosuppression and gastrointestinal toxicity, and the effect is most relevant for oral topotecan.
How serious is the interaction between Lapatinib and Topotecan?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid combining with oral topotecan. If used with intravenous topotecan, monitor blood counts closely and reduce the topotecan dose if toxicity occurs.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
