Drug & supplement interaction

Melatonin + Clobazam

Clobazam brand names: Frisium, Onfi, Sympazan.

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

Clobazam falls into 2 drug categories that Melatonin can interact with; the most serious is rated moderate. Theoretically, taking melatonin might increase the sedative effects of CNS depressants.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Melatonin and Clobazam

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Melatonin interacts with whole categories of medication. Clobazam falls into 2 of those categories, so it can interact with Melatonin in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CNS DEPRESSANTS

1 of 2

Why this applies to Clobazam

Clobazam falls under CNS DEPRESSANTS — the group Melatonin interacts with.

Theoretically, taking melatonin might increase the sedative effects of CNS depressants.
Melatonin has sedative effects. Theoretically, concomitant use of melatonin with alcohol, benzodiazepines, or other sedative drugs might cause additive sedation.
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 melatonin and clobazam (Onfi, Sympazan) can make you sleepy, so stacking them may add up. Clobazam is a benzodiazepine that already calms brain activity to control seizures, and melatonin sends its own "time to wind down" signal. Together you might feel groggier, more drowsy, dizzy, or slow to react, especially in the morning or when getting up to walk.

This concern is theoretical, based on how the two work rather than strong studies, so it isn't a guaranteed problem and many people use both without issues. Still, since clobazam is a seizure medicine, don't change anything on your own. Check with your pharmacist or doctor first, and be extra careful with driving until you know how the combination affects you.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Foster BC, Cvijovic K, Boon HS, et al. Melatonin Interaction Resulting in Severe Sedation. J Pharm Pharm Sci 2015;18(2):124-31. PubMed
Moderate

ANTICONVULSANTS

2 of 2

Clobazam also falls under ANTICONVULSANTS.

Theoretically, melatonin may reduce the effects of anticonvulsants. Some clinical research suggests that melatonin may increase the frequency of seizures in certain patients, particularly children with neurological impairment.
Severity Moderate Likelihood Possible Evidence B

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 thing to keep an eye on with this pairing. Clobazam is doing important work for you or your child by calming down the abnormal electrical activity that triggers Lennox-Gastaut seizures. The concern with melatonin isn't really about how clobazam is broken down. Instead, some clinical research suggests melatonin itself may, in certain people, actually bump up seizure frequency, especially in children who already have neurological challenges.

So the worry is a possible loss of seizure control, meaning more seizures slipping through, not a clobazam overdose. To be fair, this evidence is mixed and not seen in everyone. Please don't start, stop, or change either one on your own. Talk with your neurologist or pharmacist first so they can weigh it for your specific situation and watch seizure activity closely.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sheldon SH. Pro-convulsant effects of oral melatonin in neurologically disabled children. Lancet 1998;351:1254. PubMed
  2. Stewart LS. Endogenous melatonin and epileptogenesis: facts and hypothesis. Int J Neurosci 2001;107:77-85.. 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

Melatonin Also Interacts With Other Medications

Melatonin has 1,115 moderate, 345 minor known drug interactions in our database — the Clobazam one above is among them. If you take anything else, check it against the full list below.

Moderate 1,115 Minor 345 No known interaction 1,370 (incl. Clobazam)
Taking anything else?

Check Another of Your Medications Against Melatonin

Covers the 2,830 medications we’ve checked against Melatonin. Pick one to open its full report.

From our Q&A

Questions About Melatonin or Clobazam

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Melatonin or Clobazam, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Clobazam

This page covers Melatonin only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Clobazam page lists 109 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 Grapefruit (major).

By severity: 8 major · 85 moderate · 16 minor.

From our pharmacist’s overview on the Clobazam page

“Clobazam (Onfi, Sympazan, Frisium) is a benzodiazepine for seizures, so extra sedation is a real safety hazard rather than a nuisance, and that is what most of this list adds. The great majority of these supplements and herbs deepen drowsiness, alcohol in any form among the most serious pairings.”

Reviewed by 2 · Jul 18, 2026

Open the Clobazam interaction page

One more smart check

Taking Melatonin as Part of a Dietary Supplement Product? Check It for Interactions

We hold 2,885 real supplement products containing Melatonin, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Melatonin. Your product may carry other ingredients that interact with Clobazam too, on top of Melatonin — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Melatonin and Clobazam 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 Melatonin
Top 5%

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

29 days ago today
Medication Clobazam
Steady interest

#2,017 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 Melatonin

What is Melatonin?

Melatonin
  • Trouble falling asleep (insomnia)
  • Jet lag
  • Delayed sleep phase syndrome
  • Non-24-hour sleep-wake disorder
  • Shift-work sleep problems
  • Sleep problems in some children with conditions like autism or ADHD

Melatonin is a hormone your body makes naturally to help control your sleep-wake cycle, and the supplement form is widely used to help with sleep timing problems and jet lag. The evidence is strongest for certain circadian (body-clock) disorders and is more mixed for everyday insomnia. It is generally well tolerated for short-term use, but talk with your pharmacist or doctor before starting, especially for children or during pregnancy.

Read the full Melatonin monograph & all interactions
Medication

About Clobazam

What Is Clobazam Used For?

Brand names: Frisium, Onfi, Sympazan

Clobazam is used as an add-on (adjunctive) treatment for seizures linked to Lennox-Gastaut Syndrome (LGS), a severe form of childhood-onset epilepsy. It is approved for patients 2 years of age and older.

This indication applies to all available forms: Sympazan (dissolving oral film), Onfi (tablets and oral suspension), and generic clobazam tablets and oral suspension.

See full Clobazam drug information
Keep checking

Other Drugs & Melatonin

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

0Major
1,115Moderate
345Minor
1,369No known interaction
1,115 Moderate 345 Minor 1,369 No interaction
Moderate

1,115 interactions

Showing 60 of 1,115 moderate interactions — see all 1,115 on the Melatonin page.

Minor

345 interactions

Showing 60 of 345 minor interactions — see all 345 on the Melatonin page.

No interaction 1,369 drugs checked — show the list

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

Showing the 60 most looked-up of 1,369 medications checked with no known interaction — see the full Melatonin list.

See the full Melatonin interactions page
See every supplement checked against Clobazam, 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
Melatonin monograph › Uses, safety, and every drug interaction in one place Clobazam supplement interactions › Every supplement checked against Clobazam, ranked by severity Clobazam 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 Melatonin and Clobazam Together: Common Questions

Can you take Melatonin with Clobazam?
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.
Why are there 2 interactions listed for Melatonin and Clobazam?
Clobazam belongs to more than one drug category, and Melatonin interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Melatonin and Clobazam 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 Clobazam and Melatonin?

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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.