Foscarnet Injection and Ondansetron: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ondansetron
No brand names on recordFoscarnet Injection
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
An increased risk of QT interval prolongation
Interaction Deep Dive
Ondansetron prolongs the QT interval in a dose-dependent manner and postmarketing cases of torsade de pointes have been reported. Concomitant use of ondansetron with other QT-prolonging drugs may result in additive prolongation of the QT interval. If coadministration is necessary, ECG monitoring is recommended12.
Why it happens (mechanism)
Additive effects on QT interval prolongation
Common questions
Can I take Foscarnet Injection and Ondansetron together?
An increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.
How serious is the Foscarnet Injection and Ondansetron interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Foscarnet Injection or Ondansetron need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (2)
- Product Information: ZUPLENZ(R) oral soluble film, ondansetron oral soluble film. Praelia Pharmaceuticals, Inc. (per FDA), Morrisville, NC, 2013. DailyMed
- Product Information: ZOFRAN(R) intravenous injection, ondansetron HCl intravenous injection. GlaxoSmithKline (per FDA), Research Triangle Park, NC, 2012. DailyMed
Keep reading about Ondansetron
Keep reading about Foscarnet Injection
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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