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Drug interactions

Foscarnet + Sunitinib

Severity: Major

Foscarnet and Sunitinib: 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

Sunitinib can prolong the QT interval and foscarnet adds QT and electrolyte effects. The combination may increase the risk of torsades de pointes.

What this interaction means in plain words

Foscarnet and Sunitinib 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.

Foscarnet belongs to Anti Virals; Sunitinib belongs to Oncology.

Evidence level: Low

Why it happens

Additive QT prolongation with foscarnet-induced electrolyte disturbances.

What to do

Avoid if possible; otherwise monitor ECG and electrolytes regularly and correct abnormalities, reducing the sunitinib dose if QTc lengthens significantly.

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 Foscarnet with Sunitinib?

MediHelp rates the interaction as major. Foscarnet and Sunitinib 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. Sunitinib can prolong the QT interval and foscarnet adds QT and electrolyte effects. The combination may increase the risk of torsades de pointes.

How serious is the interaction between Foscarnet and Sunitinib?

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 if possible; otherwise monitor ECG and electrolytes regularly and correct abnormalities, reducing the sunitinib dose if QTc lengthens significantly.

What other medicines interact with Foscarnet?

MediHelp also lists interactions of Foscarnet with, for example, Cidofovir, Pimozide, Thioridazine. The full list is on the Foscarnet page.

Full monographs, dosing and an interaction checker in the MediHelp app

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