Drug Interaction Report

Nisoldipine and Fluconazole: Interaction Details

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

Fluconazole

Diflucan
+

Nisoldipine

Sular Sular®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Updated Aug 8, 2026
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
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 86 documented Nisoldipine interactions, 54 are rated major — 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
theoretical
Severity
Major

What happens

Increased nisoldipine exposure and an increased risk for nisoldipine toxicity

Interaction Deep Dive

Concomitant use of nisoldipine, a CYP3A4 substrate, with a CYP3A4 inhibitor such as fluconazole should generally be avoided1, as this may increase exposure to the CYP3A4 substrate and increase the risk for toxicity. If concomitant use is required use caution and monitor closely. Fluconazole-mediated enzyme inhibition may persist for 4 to 5 days after discontinuation 2.

Why it happens (mechanism)

Inhibition of CYP3A4-mediated nisoldipine metabolism by fluconazole

Common questions

Can I take Nisoldipine and Fluconazole together?

Increased nisoldipine exposure and an increased risk for nisoldipine toxicity Always confirm with your pharmacist or prescriber before making any change.

How serious is the Nisoldipine and Fluconazole 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 Nisoldipine or Fluconazole 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: SULAR(R) extended release oral tablets, nisoldipine extended release oral tablets. Shionogi Pharma, Inc, Atlanta, GA, 2010.
  2. Product Information: DIFLUCAN(R) oral tablets, suspension, fluconazole oral tablets, suspension. Roerig (per FDA), New York, NY, 2023. DailyMed
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Beyond drug–drug

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.

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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.