Ketoconazole Topical and Milsaperidone: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ketoconazole Topical
Milsaperidone
No brand names on record
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 milsaperidone exposure, an increased risk of milsaperidone-related adverse reactions and an increased risk of QT interval prolongation
Interaction Deep Dive
Coadministration of ketoconazole with milsaperidone (CYP3A4 substrate that prolong the QT interval) is contraindicated as it may cause increased milsaperidone exposure, increasing the risk for QT interval prolongation and result in life-threatening ventricular tachyarrhythmias such as torsade de pointes1. Concomitant use with ketoconazole (strong CYP3A4 inhibitor, stable dosage) in schizophrenia: Start milsaperidone 1 mg twice daily; titration, increase to 2 mg twice daily on day 2, 4 mg twice daily on day 3, and 6 mg twice daily on day 4 to reach maintenance dosage of 3 to 6 mg twice daily (starting on day 3, may alternatively continue 3 mg twice daily and titrate subsequent doses based on tolerability and response). Concomitant use in bipolar I disorder, manic or mixed episodes: Start milsaperidone 1 mg twice daily; titration, increase to 3 mg twice daily on day 2, and to maintenance dosage of 6 mg twice daily on day 3. Concomitant use (strong CYP3A4 inhibitor, initiation): Reduce milsaperidone maintenance dosage by one-half; follow titration schedule to return to original dosage once the CYP3A4 inhibitor is discontinued. Patients with schizophrenia may either follow the recommended titration schedule, or starting on day 5, continue 6 mg twice daily milsaperidone dosing. As needed, titrate subsequent doses based on tolerability and response within the recommended maintenance dosing range of 6 to 12 mg twice daily 2.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of milsaperidone; additive QT interval prolongation
Literature reports
1 report — tap to read
a) Concomitant administration of ketoconazole (a strong CYP3A4 inhibitor) (200 mg twice daily for 4 days) with a 3 mg single dose of iloperidone, increased the iloperidone AUC by 57%, the milsaperidone AUC by 55% and the P95 (iloperidone metabolite) AUC by 35% 2.
Common questions
Can I take Ketoconazole Topical and Milsaperidone together?
Increased milsaperidone exposure, an increased risk of milsaperidone-related adverse reactions and an increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ketoconazole Topical and Milsaperidone interaction?
It is rated contraindicated. These should generally not be used together.
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 "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Ketoconazole Topical or Milsaperidone 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: Ketoconazole oral tablet, ketoconazole oral tablet. Taro Pharmaceuticals U.S.A. Inc. (per DailyMed), Hawthorne, NY, 2024. DailyMed
- Product Information: BYSANTI™ oral tablets, milsaperidone oral tablets. Vanda Pharmaceuticals Inc. (Per Manufacturer), Washington, D.C. 2026. DailyMed
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