Drug Interaction Report

Lacosamide Injection and Cannabidiol: Interaction Details

A pharmacist-reviewed analysis of the Lacosamide Injection and Cannabidiol 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

Cannabidiol

Epidiolex
+

Lacosamide Injection

Motpoly Vimpat Vimpat® I.V.
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 234 documented Lacosamide Injection interactions, 230 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 CYP2C19 substrate exposure, an increased risk of CYP2C19 substrate-related adverse reactions, increased risk of CNS depression and an increased risk of sedation and somnolence

Interaction Deep Dive

Use lacosamide with extreme caution in combination with cannabidiol (CNS depressant) due to the potential for CNS depression, as well as other cognitive and/or neuropsychiatric adverse reactions1. Coadministration of cannabidiol (moderate CYP2C19 inhibitor) with lacosamide (CYP2C19 substrate) may increase lacosamide exposure and may increase the risk of adverse reactions. Consider a dosage reduction of lacosamide, as clinically appropriate, when concomitantly used with cannabidiol. Additionally, concomitant use of cannabidiol with lacosamide may increase the risk of sedation and somnolence. Monitor for somnolence and sedation and advise patients not to drive or operate machinery until they have gained sufficient experience on cannabidiol 2.

Why it happens (mechanism)

Inhibition of CYP2C19-substrate metabolism by cannabidiol; additive CNS depression

Common questions

Can I take Lacosamide Injection and Cannabidiol together?

Increased CYP2C19 substrate exposure, an increased risk of CYP2C19 substrate-related adverse reactions, increased risk of CNS depression and an increased risk of sedation and somnolence Always confirm with your pharmacist or prescriber before making any change.

How serious is the Lacosamide Injection and Cannabidiol 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 Lacosamide Injection or Cannabidiol 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: Motpoly XR oral extended-release capsules, lacosamide oral extended-release capsules. Aucta Pharmaceuticals, Inc, Piscataway, NJ, 2023. DailyMed
  2. Product Information: EPIDIOLEX(R) oral solution, cannabidiol oral solution. Jazz Pharmaceuticals, Inc. (per FDA), Palo Alto, CA, 2025. DailyMed
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Cannabidiol

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Lacosamide Injection

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All Lacosamide Injection interactions (234) Lacosamide Injection drug information
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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.