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Drug interactions

Quinine + Tucatinib

Severity: Major

Quinine and Tucatinib: 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

Tucatinib inhibits CYP3A4 and may raise quinine concentrations, increasing toxicity risk including QT prolongation. The reverse effect on tucatinib is unlikely to be significant.

What this interaction means in plain words

Quinine and Tucatinib 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.

Quinine belongs to Anti Parasitic; Tucatinib belongs to Oncology.

Evidence level: Moderate

Why it happens

Tucatinib inhibits CYP3A4, reducing quinine clearance.

What to do

Avoid the combination where possible. If needed, monitor ECG, glucose and signs of cinchonism.

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?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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Frequently asked questions

Can I take Quinine with Tucatinib?

MediHelp rates the interaction as major. Quinine and Tucatinib 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. Tucatinib inhibits CYP3A4 and may raise quinine concentrations, increasing toxicity risk including QT prolongation. The reverse effect on tucatinib is unlikely to be significant.

How serious is the interaction between Quinine and Tucatinib?

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 the combination where possible. If needed, monitor ECG, glucose and signs of cinchonism.

What other medicines interact with Quinine?

MediHelp also lists interactions of Quinine with, for example, Arsenic trioxide, Dofetilide, Dronedarone. The full list is on the Quinine page.

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