Drug interactions
Foscarnet + Voriconazole
Severity: Major
Foscarnet and Voriconazole: 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
Both foscarnet and voriconazole can prolong the QT interval, and foscarnet commonly causes hypokalemia, hypomagnesemia, and hypocalcemia. This adds to the risk of torsades de pointes.
What this interaction means in plain words
Foscarnet and Voriconazole 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; Voriconazole belongs to Anti Fungals.
Why it happens
Additive QT prolongation, worsened by foscarnet-induced electrolyte disturbances.
What to do
Monitor the ECG and check potassium, magnesium and calcium regularly, and correct abnormalities promptly. Avoid the combination in patients with baseline QT prolongation.
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 Voriconazole
- Avanafil + Voriconazole Contraindicated
- Butabarbital + Voriconazole Contraindicated
- Carbamazepine + Voriconazole Contraindicated
- Conivaptan + Voriconazole Contraindicated
- Dihydroergotamine intranasal + Voriconazole Contraindicated
- Dihydroergotamine + Voriconazole Contraindicated
Other interactions of Foscarnet
- Cidofovir + Foscarnet Contraindicated
- Foscarnet + Pimozide Contraindicated
- Foscarnet + Thioridazine Contraindicated
- Foscarnet + Vandetanib Contraindicated
- Adagrasib + Foscarnet Major
- Adefovir + Foscarnet Major
Frequently asked questions
Can I take Foscarnet with Voriconazole?
MediHelp rates the interaction as major. Foscarnet and Voriconazole 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. Both foscarnet and voriconazole can prolong the QT interval, and foscarnet commonly causes hypokalemia, hypomagnesemia, and hypocalcemia. This adds to the risk of torsades de pointes.
How serious is the interaction between Foscarnet and Voriconazole?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor the ECG and check potassium, magnesium and calcium regularly, and correct abnormalities promptly. Avoid the combination in patients with baseline QT prolongation.
What other medicines interact with Voriconazole?
MediHelp also lists interactions of Voriconazole with, for example, Avanafil, Butabarbital, Carbamazepine. The full list is on the Voriconazole page.
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