Drug Interaction Report

Nimodipine and Dexamethasone: Interaction Details

A pharmacist-reviewed analysis of the Nimodipine and Dexamethasone 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

Dexamethasone

No brand names on record
+

Nimodipine

Nimotop Nimotop® Nymalize Nymalize®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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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 77 documented Nimodipine interactions, 27 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

Reduced nimodipine plasma concentrations and reduced nimodipine efficacy

Interaction Deep Dive

Concomitant use of dexamethasone (a CYP3A4 inducer)2 and nimodipine (a CYP3A4 substrate) should be avoided. Concurrent use may significantly decrease nimodipine plasma levels, and may result in reduction of antihypertensive effects of nimodipine 1.

Why it happens (mechanism)

Induction of CYP3A4-mediated metabolism of nimodipine by dexamethasone

Common questions

Can I take Nimodipine and Dexamethasone together?

Reduced nimodipine plasma concentrations and reduced nimodipine efficacy Always confirm with your pharmacist or prescriber before making any change.

How serious is the Nimodipine and Dexamethasone 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 Nimodipine or Dexamethasone 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: nimodipine oral capsules, nimodipine oral capsules. Caraco Pharmaceutical Laboratories, Ltd. (per DailyMed), Detroit, MI, 2012. DailyMed
  2. Product Information: DEXAMETHASONE oral tablets, oral solution, dexamethasone oral tablets, oral solution. Roxane Laboratories, Inc. (per DailyMed), Columbus, OH, 2007. DailyMed
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Dexamethasone

Keep reading about Dexamethasone

All Dexamethasone interactions (74)
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Nimodipine

Keep reading about Nimodipine

All Nimodipine interactions (77) Nimodipine drug information
Also serious with: Boceprevir Conivaptan Clarithromycin Voriconazole
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:

Dexamethasone + Activated Charcoal Grapefruit Lily-of-the-valley St. John's Wort Acacia Rigidula Active Hexose Correlated Compound (ahcc) Adrafinil African Wild Potato + 213 more
Nimodipine + Activated Charcoal American Hellebore American Mistletoe Grapefruit St. John's Wort Tyramine Acacia Rigidula Adrafinil + 219 more

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.