Drug Interaction Report

Nimodipine and Dantrolene: Interaction Details

A pharmacist-reviewed analysis of the Nimodipine and Dantrolene 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

Dantrolene

Dantrium Revonto Ryanodex
+

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

Severe hyperkalemia with cardiovascular collapse

Interaction Deep Dive

Concomitant use of dantrolene and calcium channel blockers is not recommended. Cardiovascular collapse associated with severe hyperkalemia has been reported with concurrent use of calcium channel blockers1. Hyperkalemia and cardiac depression were reported in a patient with coronary artery disease susceptible to malignant hyperthermia treated with verapamil who received parenteral dantrolene perioperatively. The patient did not have these adverse effects in a subsequent surgery with dantrolene and nifedipine 2. If concurrent use is necessary, monitor blood pressure and serum potassium.

Why it happens (mechanism)

Unknown

Literature reports

1 report — tap to read

a) A study described the anesthetic experiences of a malignant hyperthermia-susceptible patient with coronary artery disease treated with verapamil who developed hyperkalemia and myocardial depression following parenteral dantrolene administration. Hyperkalemia and myocardial depression did not occur following parenteral dantrolene when nifedipine was substituted for verapamil for a subsequent operation in the same patient 2.

Common questions

Can I take Nimodipine and Dantrolene together?

Severe hyperkalemia with cardiovascular collapse Always confirm with your pharmacist or prescriber before making any change.

How serious is the Nimodipine and Dantrolene 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.

Questions for your pharmacist

  • Does my dose of Nimodipine or Dantrolene 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: RYANODEX(R) intravenous injection suspension, dantrolene sodium intravenous injection suspension. Eagle Pharmaceuticals, Inc. (per manufacturer), Woodcliff Lake, NJ, 2014. DailyMed
  2. Rubin AS & Zablocki AD: Hyperkalemia, verapamil, and dantrolene. Anesthesiology 1987; 66:246-249. PubMed
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Dantrolene

Keep reading about Dantrolene

All Dantrolene interactions (21)
Also serious with: Hydromorphone Rectal Buprenorphine Nisoldipine Methotrexate Injection
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:

Dantrolene + Activated Charcoal Beer Procaine Siberian Cocklebur Wine Alfalfa Angelica Archangelica Arrach + 69 more
Nimodipine + Activated Charcoal American Hellebore American Mistletoe Grapefruit St. John's Wort Tyramine Acacia Rigidula Adrafinil + 219 more

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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.