Drug interactions
Fexinidazole + Foscarnet
Severity: Major
Fexinidazole and Foscarnet: 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
Fexinidazole can prolong the QT interval and its labeling advises against combination with other QT-prolonging agents. Foscarnet adds QT liability and may cause hypocalcemia and hypomagnesemia, increasing the likelihood of torsade de pointes.
What this interaction means in plain words
Fexinidazole and Foscarnet 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.
Why it happens
Additive QT prolongation, with foscarnet-induced electrolyte depletion as an added risk.
What to do
Avoid concurrent use; consider an alternative antiviral or defer foscarnet where feasible. If unavoidable, perform ECG monitoring and correct potassium, magnesium and calcium beforehand.
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 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 Fexinidazole with Foscarnet?
MediHelp rates the interaction as major. Fexinidazole and Foscarnet 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. Fexinidazole can prolong the QT interval and its labeling advises against combination with other QT-prolonging agents. Foscarnet adds QT liability and may cause hypocalcemia and hypomagnesemia, increasing the likelihood of torsade de pointes.
How serious is the interaction between Fexinidazole and Foscarnet?
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 concurrent use; consider an alternative antiviral or defer foscarnet where feasible. If unavoidable, perform ECG monitoring and correct potassium, magnesium and calcium beforehand.
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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