Drug interactions
Foscarnet + Granisetron
Severity: Major
Foscarnet and Granisetron: 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
Foscarnet can prolong the QT interval and causes electrolyte disturbances such as low calcium, magnesium and potassium. Granisetron adds a small QT effect, so the combination can increase the risk of torsades de pointes.
What this interaction means in plain words
Foscarnet and Granisetron 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; Granisetron belongs to Gastrointestinal Tract.
Why it happens
Additive QT prolongation, amplified by foscarnet-induced electrolyte depletion.
What to do
Monitor the ECG and serum electrolytes, replacing potassium, magnesium and calcium as needed. Use a different antiemetic if the QTc becomes prolonged.
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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References
Other interactions of Granisetron
- Apomorphine + Granisetron Contraindicated
- Amiodarone + Granisetron Major
- Amisulpride + Granisetron Major
- Arsenic trioxide + Granisetron Major
- Artemether / lumefantrine + Granisetron Major
- Artemether + Granisetron Major
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 Granisetron?
MediHelp rates the interaction as major. Foscarnet and Granisetron 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 can prolong the QT interval and causes electrolyte disturbances such as low calcium, magnesium and potassium. Granisetron adds a small QT effect, so the combination can increase the risk of torsades de pointes.
How serious is the interaction between Foscarnet and Granisetron?
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 serum electrolytes, replacing potassium, magnesium and calcium as needed. Use a different antiemetic if the QTc becomes prolonged.
What other medicines interact with Granisetron?
MediHelp also lists interactions of Granisetron with, for example, Apomorphine, Amiodarone, Amisulpride. The full list is on the Granisetron page.
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