Drug interactions
Quinidine + Topotecan
Severity: Major
Quinidine 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
Quinidine inhibits P-gp and may increase topotecan absorption and exposure, especially with oral topotecan. This may worsen myelosuppression and gastrointestinal toxicity.
What this interaction means in plain words
Quinidine 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.
Quinidine belongs to Anti Parasitic; Topotecan belongs to Oncology.
Why it happens
Quinidine inhibits P-gp-mediated efflux of topotecan, increasing systemic exposure.
What to do
Avoid quinidine with oral topotecan. With IV topotecan, monitor blood counts closely and reduce the dose for neutropenia.
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?
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Other interactions of Quinidine
- Adagrasib + Quinidine Contraindicated
- Arsenic trioxide + Quinidine Contraindicated
- Artemether / lumefantrine + Quinidine Contraindicated
- Chloroquine + Quinidine Contraindicated
- Dofetilide + Quinidine Contraindicated
- Dronedarone + Quinidine Contraindicated
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 Quinidine with Topotecan?
MediHelp rates the interaction as major. Quinidine 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. Quinidine inhibits P-gp and may increase topotecan absorption and exposure, especially with oral topotecan. This may worsen myelosuppression and gastrointestinal toxicity.
How serious is the interaction between Quinidine 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 quinidine with oral topotecan. With IV topotecan, monitor blood counts closely and reduce the dose for neutropenia.
What other medicines interact with Quinidine?
MediHelp also lists interactions of Quinidine with, for example, Adagrasib, Arsenic trioxide, Artemether / lumefantrine. The full list is on the Quinidine page.
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