Iloperidone and Arsenic Trioxide: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Iloperidone
Arsenic Trioxide
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
Increased risk of QT interval prolongation and torsade de pointes
Interaction Deep Dive
. Avoid the concomitant use of iloperidone and drugs that are known to cause QT prolongation, such as arsenic trioxide, due to the potential for additive effects on the QT interval and increased risk of torsade de pointes2. Both arsenic trioxide and iloperidone may prolong QT interval 12.
Why it happens (mechanism)
Additive QT interval prolongation
Literature reports
2 reports — tap to read
a) QT/QTc prolongation and torsade de pointes as well as complete heart block have been reported with arsenic trioxide. Sixteen of 40 patients (40%) with over 460 ECG tracings had at least one ECG tracing with a QTc interval greater than 500 msec. Prolongation of the QTc was observed between 1 and 5 weeks after arsenic trioxide infusion, and then returned towards baseline by the end of 8 weeks after arsenic trioxide infusion. Gender and age were not associated risk factors. Patients were treated with arsenic trioxide for refractory or relapsed APL 1.
b) In an open-label QTc study of patients with schizophrenia or schizoaffective disorder (n=160), iloperidone 12 mg twice a day was associated with QTc prolongation of 9 msec 2.
Common questions
Can I take Iloperidone and Arsenic Trioxide together?
Increased risk of QT interval prolongation and torsade de pointes Always confirm with your pharmacist or prescriber before making any change.
How serious is the Iloperidone and Arsenic Trioxide 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 Iloperidone or Arsenic Trioxide 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: TRISENOX(R) IV injection, arsenic trioxide IV injection. Cephalon, Inc, Frazer, PA, 2010.
- Product Information: FANAPT(R) oral tablets, iloperidone oral tablets. Vanda Pharmaceuticals Inc (per FDA), Washington, DC, 2024. DailyMed
Keep reading about Iloperidone
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