Vardenafil and Ketoconazole Topical: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Vardenafil
Ketoconazole Topical
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 vardenafil exposure and an increased risk of QT interval prolongation
Interaction Deep Dive
Coadministration of ketoconazole, a strong CYP3A4 inhibitor that may prolong the QT interval and vardenafil, a CYP3A4 substrates that are known to prolong the QT interval is contraindicated1. Coadministration use led to increased vardenafil exposure in a clinical study 3. Use of the orally disintegrating tablet formulation of vardenafil is not recommended with ketoconazole 2. Concomitant use may result in additive effects on the QT interval, increasing the risk for serious ventricular arrhythmias including torsades de pointes. If concomitant use of ketoconazole with vardenafil film-coated tablets, use caution and do not to exceed vardenafil 5 mg every 24 hours if given with ketoconazole 200 mg, or vardenafil 2.5 mg every 24 hours if given with ketoconazole 400 mg 3.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of vardenafil; additive QT interval prolongation
Literature reports
2 reports — tap to read
a) In a pharmacokinetic study in healthy volunteers, coadministration of ketoconazole 200 mg daily with a single dose of vardenafil 5 mg resulted in a 4-fold increase in the vardenafil Cmax and a 10-fold increase in the vardenafil AUC compared with use of vardenafil alone 3.
b) In a single-dose, double-blind, randomized, placebo- and active-controlled crossover study, 59 male patients receiving vardenafil 10 mg (therapeutic), vardenafil 80 mg (supratherapeutic), or moxifloxacin 400 mg experienced similar increases in QTc interval measurements taken one hour after dosing. Single-dose administration resulted in a placebo-subtracted mean change from baseline QT (uncorrected) of 3 msec (90% confidence interval [CI]: 1, 5) for moxifloxacin 400 mg and -2 msec (90% CI: -4, 0) for both vardenafil 10 mg and 80 mg. Mean change from baseline Fridericia QT correction was 10 msec (90% CI: 8, 11) for vardenafil 80 mg, and 8 msec (90% CI: 6, 9) for both vardenafil 10 mg and moxifloxacin. Mean change from baseline for individual QT correction was 4 msec (90% CI: 3, 6) for vardenafil 10 mg, 6 msec (90% CI: 4, 7) for vardenafil 80 mg, and 7 msec (90% CI: 5, 8) for moxifloxacin. Mean increases in heart rate with vardenafil 10 mg and 80 mg were 5 and 6 beats per minute, respectively, compared with placebo 32.
Common questions
Can I take Vardenafil and Ketoconazole Topical together?
Increased vardenafil exposure and an increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.
How serious is the Vardenafil 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Vardenafil 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 (3)
- Product Information: Ketoconazole oral tablet, ketoconazole oral tablet. Taro Pharmaceuticals U.S.A. Inc. (per DailyMed), Hawthorne, NY, 2024. DailyMed
- Product Information: STAXYN(R) oral disintegrating tablets, vardenafil HCl oral disintegrating tablets. GlaxoSmithKline (per FDA), Research Triangle Park, NC, 2023. DailyMed
- Product Information: LEVITRA(R) oral tablets, vardenafil HCl oral tablets. Bayer Health Care Pharmaceuticals Inc (per FDA), Whippany, NJ, 2023. DailyMed
Keep reading about Vardenafil
Keep reading about Ketoconazole Topical
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