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Drug interactions

Foscarnet + Tetrabenazine

Severity: Major

Foscarnet and Tetrabenazine: major interaction.

Last updated Sources: US FDA label

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

Tetrabenazine can cause a modest QT prolongation, and foscarnet has its own QT liability and electrolyte effects. Combining them may raise the risk of torsade de pointes, especially in patients with other risk factors.

What this interaction means in plain words

Foscarnet and Tetrabenazine 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; Tetrabenazine belongs to Central Nervous System.

Evidence level: Low

Why it happens

Additive QT prolongation, with foscarnet-related electrolyte disturbances contributing.

What to do

Avoid the combination if possible. If both are needed, obtain a baseline ECG, correct electrolytes and monitor ECG during treatment.

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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References

Frequently asked questions

Can I take Foscarnet with Tetrabenazine?

MediHelp rates the interaction as major. Foscarnet and Tetrabenazine 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. Tetrabenazine can cause a modest QT prolongation, and foscarnet has its own QT liability and electrolyte effects. Combining them may raise the risk of torsade de pointes, especially in patients with other risk factors.

How serious is the interaction between Foscarnet and Tetrabenazine?

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 if possible. If both are needed, obtain a baseline ECG, correct electrolytes and monitor ECG during treatment.

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.

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