Granisetron Transdermal Patch and Posaconazole: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Posaconazole
Granisetron Transdermal Patch
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
Use of posaconazole has been associated with QT interval prolongation and torsade de pointes has been reported on rare occasions with posaconazole therapy. Due to the potential for additive effects on the QT interval and increased risk of serious cardiovascular effects, caution is advised when coadministering posaconazole with other drugs that may prolong the QT interval2, such as granisetron 1. If concurrent therapy is required, monitoring for QT interval prolongation may be warranted.
Why it happens (mechanism)
Additive effects on the QT interval
Common questions
Can I take Granisetron Transdermal Patch and Posaconazole together?
An increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.
How serious is the Granisetron Transdermal Patch and Posaconazole 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.
Questions for your pharmacist
- Does my dose of Granisetron Transdermal Patch or Posaconazole 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: KYTRIL(R) IV injection, granisetron HCl IV injection. Genentech USA, Inc, South San Francisco, CA, 2011.
- Product Information: NOXAFIL(R) oral suspension, posaconazole oral suspension. Schering Corporation, Kenilworth, NJ, 2010. DailyMed
Keep reading about Posaconazole
Keep reading about Granisetron Transdermal Patch
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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