Drug & supplement interaction

Cannabidiol (cbd) + Trimethadione

Trimethadione brand name: Tridione.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Cannabidiol (cbd) has a moderate interaction with Trimethadione. Theoretically, cannabidiol might have additive effects if used with other CNS depressants.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Cannabidiol (cbd) and Trimethadione

Here is the interaction we found between these two, with the evidence behind it.

Moderate

CNS DEPRESSANTS

Why this applies to Trimethadione

Trimethadione falls under CNS DEPRESSANTS — the group Cannabidiol (cbd) interacts with.

Theoretically, cannabidiol might have additive effects if used with other CNS depressants.
Preliminary clinical research, case reports, and animal studies suggest that high dose cannabidiol has sedative and hypnotic effects. Theoretically, concomitant use of cannabidiol with drugs with sedative and anesthetic properties may cause additive therapeutic and adverse effects.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the simple version: both CBD and trimethadione can have a calming, slowing effect on the brain. When you put them together, those effects may stack up. So someone taking both could feel more drowsy, foggy, or out of it than usual, and may notice things like dizziness or trouble concentrating.

I want to be honest about how solid this is. This concern is mostly theoretical, based on how these substances behave rather than strong studies in people, and it tends to matter more with higher CBD doses. Trimethadione is also an older, rarely used seizure medicine, so good data is limited. Please don't change anything on your own. Check in with your pharmacist or doctor before combining them, especially watching for extra sleepiness.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Carlini EA, Cunha JM. Hypnotic and antiepileptic effects of cannabidiol. J Clin Pharmacol 1981;21(8-9 Suppl):417S-27S. PubMed
  2. Monti JM. Hypnoticlike effects of cannabidiol in the rat. Psychopharmacology (Berl) 1977;55(3):263-5. PubMed
  3. Pickens JT. Sedative activity of cannabis in relation to its delta'-trans-tetrahydrocannabinol and cannabidiol content. Br J Pharmacol 1981;72(4):649-56.
  4. Perez-Vilar S, Karami S, Long K, Leishear K. Cannabidiol exposures in the United States, National Poison Data System, July 2014-June 2021. Clin Toxicol (Phila) 2022. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Cannabidiol (cbd) Also Interacts With Other Medications

Cannabidiol (cbd) has 1,050 moderate known drug interactions in our database — the Trimethadione one above is one of them. If you take anything else, check it against the full list below.

Moderate 1,050 No known interaction 1,780 (incl. Trimethadione)
Taking anything else?

Check Another of Your Medications Against Cannabidiol (cbd)

Covers the 2,830 medications we’ve checked against Cannabidiol (cbd). Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Trimethadione

This page covers Cannabidiol (cbd) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Trimethadione page lists 124 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Kava (major).

By severity: 7 major · 100 moderate · 17 minor.

Open the Trimethadione interaction page

How much people look this up

Where Cannabidiol (cbd) and Trimethadione Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Cannabidiol (cbd)
Top half

#531 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Trimethadione
Steady interest

#2,039 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Cannabidiol (cbd)

What is Cannabidiol (cbd)?

  • Anxiety and stress
  • Sleep problems
  • Chronic pain
  • Certain seizure disorders
  • Inflammation

CBD is a compound from the cannabis (hemp) plant that does not cause a 'high.' It has strong evidence only for certain rare seizure disorders (as a prescription drug), while most other popular uses are still backed by limited or early research. Product quality varies a lot, so talk with your pharmacist or doctor before using it, especially if you take other medicines.

Read the full Cannabidiol (cbd) monograph & all interactions
Medication

About Trimethadione

What Is Trimethadione Used For?

Brand name: Tridione

  • Trimethadione is used to control absence seizures (petit mal; a type of seizure in which there is a very short loss of awareness during which the person may stare straight ahead or blink his eyes and does not respond to others) when other medications will not work. Trimethadione is in a class of medications called anticonvulsants. It works by reducing abnormal electrical activity in the brain.

See full Trimethadione drug information
Keep checking

Other Drugs & Cannabidiol (cbd)

Browse every other medication we’ve checked against Cannabidiol (cbd) — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
1,050Moderate
0Minor
1,779No known interaction
1,050 Moderate 1,779 No interaction
Moderate

1,050 interactions

Showing 60 of 1,050 moderate interactions — see all 1,050 on the Cannabidiol (cbd) page.

No interaction 1,779 drugs checked — show the list

We also checked Cannabidiol (cbd) against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 1,779 medications checked with no known interaction — see the full Cannabidiol (cbd) list.

See the full Cannabidiol (cbd) interactions page
See every supplement checked against Trimethadione, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Cannabidiol (cbd) monograph › Uses, safety, and every drug interaction in one place Trimethadione supplement interactions › Every supplement checked against Trimethadione, ranked by severity Trimethadione drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Cannabidiol (cbd) and Trimethadione Together: Common Questions

Can you take Cannabidiol (cbd) with Trimethadione?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Cannabidiol (cbd) and Trimethadione interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Trimethadione and Cannabidiol (cbd)?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.