Arsenic Trioxide Injection and Isoflurane: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Isoflurane
Arsenic Trioxide 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 cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest)
Interaction Deep Dive
Even though no formal drug interaction studies have been done, the coadministration of isoflurane and other drugs known to prolong the QTc interval, including arsenic trioxide is not recommended2, as it may increase risk of QT interval prolongation with rare instances of torsade de pointes. Hence, monitor QT interval 3 and ECGs more frequently in patients when it is not feasible to avoid concomitant use. Discontinue or replace with an alternative drug that does not prolong the QT/QTc interval while the patient is using arsenic trioxide 1.
Why it happens (mechanism)
Additive QT interval prolongation
Literature reports
1 report — tap to read
a) In a single-arm trial of arsenic trioxide (0.15 mg/kg daily), 16 of 40 patients (40%) 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 1.
Common questions
Can I take Arsenic Trioxide Injection and Isoflurane together?
An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Always confirm with your pharmacist or prescriber before making any change.
How serious is the Arsenic Trioxide Injection and Isoflurane 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 Arsenic Trioxide Injection or Isoflurane 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 (3)
- Product Information: TRISENOX(R) intravenous injection, arsenic trioxide intravenous injection. Teva Pharmaceuticals USA Inc (per FDA), Parsippany, nj, 2020. DailyMed
- Owens R: Risk assessment for antimicrobial agent-induced QTc prolongation and torsades de pointes. Pharmacother 2001; 21(3):310-319.
- Product Information: FORANE inhalation liquid, isoflurane inhalation liquid. Baxter Healthcare Corporation (per FDA), Deerfield, IL, 2024. DailyMed
Keep reading about Isoflurane
Keep reading about Arsenic Trioxide Injection
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