Drug Interaction Report

Solifenacin and Ketoconazole Topical: Interaction Details

A pharmacist-reviewed analysis of the Solifenacin and Ketoconazole Topical interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Solifenacin

Vesicare
+

Ketoconazole Topical

Extina® Foam Ketozole® Cream Kuric Nizoral AD® Shampoo Nizoral® Cream Nizoral® Shampoo Xolegel®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
LinkedIn
Interaction severity
Contraindicated
These should generally not be used together.
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.

Of 72 documented Solifenacin interactions, 1 is rated contraindicated — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
probable
Severity
Contraindicated

What happens

Increased solifenacin exposure and increased risk of QT interval prolongation

Interaction Deep Dive

Coadministration of solifenacin, a CYP3A4 substrate that prolong QT2 and ketoconazole, a strong CYP3A4 inhibitor that prolong the QT interval is contraindicated. Concomitant use may result in elevated solifenacin exposure, increasing the risk for QT interval prolongation and life-threatening ventricular tachyarrhythmias, including torsades de pointes 1. If concomitant use is required, do not exceed 5 mg solifenacin once daily when used concomitantly with a potent CYP3A4 inhibitor such as ketoconazole. In a crossover study, following blockade of CYP3A4 by coadministration of the potent CYP3A4 inhibitor, ketoconazole 400 mg, once daily for 21 days, the mean Cmax and AUC of solifenacin increased by 1.5 and 2.7-fold, respectively 2.

Why it happens (mechanism)

Inhibition of CYP3A4-mediated metabolism of solifenacin; additive QT interval prolongation

Literature reports

1 report — tap to read

a) In a crossover study, following blockade of CYP3A4 by coadministration of the potent CYP3A4 inhibitor, ketoconazole 400 mg, once daily for 21 days, the mean Cmax and AUC of solifenacin increased by 1.5 and 2.7-fold, respectively 2.

Common questions

Can I take Solifenacin and Ketoconazole Topical together?

Increased solifenacin exposure and increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.

How serious is the Solifenacin and Ketoconazole Topical 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 Solifenacin or Ketoconazole Topical 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)

  1. Product Information: Ketoconazole oral tablet, ketoconazole oral tablet. Taro Pharmaceuticals U.S.A. Inc. (per DailyMed), Hawthorne, NY, 2024. DailyMed
  2. Product Information: VESIcare(R) oral tablets, solifenacin succinate oral tablets. Astellas Pharma US Inc (per FDA), Northbrook, IL, 2019. DailyMed
Was this write-up helpful?
Solifenacin

Keep reading about Solifenacin

All Solifenacin interactions (72)
Also serious with: Felbamate Eribulin Injection Sertraline Dasatinib
Ketoconazole Topical

Keep reading about Ketoconazole Topical

All Ketoconazole Topical interactions (546) Ketoconazole Topical drug information
Also serious with: Colchicine Conivaptan Crizotinib Dabrafenib

Check another combination

Our instant two-drug interaction checker is almost here.

Coming soon

The instant two-drug checker is on its way.

In the meantime, browse the directory below to look up any drug and see its documented interactions.

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
This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.