Fluconazole and Arsenic Trioxide: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Fluconazole
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
An increased risk of QT interval prolongation
Interaction Deep Dive
Case reports have described QT prolongation and torsades de points associated with fluconazole56. Arsenic trioxide is known to prolong the QTc interval at the recommended therapeutic dose. Even though no formal drug interaction studies have been done, do not administer arsenic trioxide with other drugs which are also known or have the potential to prolong the QTc interval 1, such as fluconazole as it may increase the risk of QT interval prolongation 23.
Why it happens (mechanism)
Additive QT interval prolongation
Literature reports
2 reports — tap to read
a) QT/QTc prolongation should be expected during treatment with arsenic trioxide and torsade de pointes as well as complete heart block has been reported. Over 460 ECG tracings from 40 patients with refractory or relapsed APL treated with arsenic trioxide were evaluated for QTc prolongation. Sixteen 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. In these ECG evaluations, women did not experience more pronounced QT prolongation than men, and there was no correlation with age 4.
b) Case reports have described QT prolongation and torsades de points associated with fluconazole 56.
Common questions
Can I take Fluconazole and Arsenic Trioxide together?
An increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.
How serious is the Fluconazole 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Fluconazole 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 (6)
- Product Information: Trisenox(R), arsenic trioxide. Cell Therapeutics, Inc. Seattle, WA, 2001. DailyMed
- Product Information: DIFLUCAN(R) oral tablets, suspension, fluconazole oral tablets, suspension. Roerig (per FDA), New York, NY, 2024. DailyMed
- Product Information: DIFLUCAN(R) intravenous injection, fluconazole intravenous injection. Roerig (per FDA), New York, NY, 2024. DailyMed
- Product Information: Trisenox(R), aresenic trioxide injection. Cell Therapeutics Inc. Seattle, WA, 2001. DailyMed
- Khazan M & Mathis AS: Probable cause of torsades de pointes induced by fluconazole. Pharmacotherapy 2002; 22(12):1632-1637.
- Wassmann S, Nickenig G, & Bohm M: Long QT syndrome and torsade de pointes in a patient receiving fluconazole. Ann Intern Med 1999; 131:797. PubMed
Keep reading about Fluconazole
Keep reading about Arsenic Trioxide
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.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist