Drug & supplement interaction

Calamus + Felbamate

Felbamate brand name: Felbatol.

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

Calamus has a moderate interaction with Felbamate. Theoretically, concurrent use of CNS depressants and calamus might have an additive effect and increase the risk of sedative effects.

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

Calamus and Felbamate

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

Moderate

CNS DEPRESSANTS

Why this applies to Felbamate

Felbamate falls under CNS DEPRESSANTS — the group Calamus interacts with.

Theoretically, concurrent use of CNS depressants and calamus might have an additive effect and increase the risk of sedative effects.
Animal research shows that calamus is a CNS depressant and increases gamma-aminobutyric acid levels.
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 gist with Felbamate and calamus. Felbamate calms overactive brain signals to control seizures, and in animal studies calamus seems to do something similar by raising a calming brain chemical called GABA. Put them together and the worry is simply that they could stack up, leaving you more drowsy, dizzy, sluggish, or foggy than usual.

I want to be honest about the evidence here: this is theoretical, based on lab and animal work, not human studies, so we can't say it will definitely happen. On top of that, calamus has real safety concerns of its own (it contains beta-asarone, which the FDA banned from foods). Before mixing the two, please check with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  2. Koo, B. S., Park, K. S., Ha, J. H., Park, J. H., Lim, J. C., and Lee, D. U. Inhibitory effects of the fragrance inhalation of essential oil from Acorus gramineus on central nervous system. Biol Pharm.Bull. 2003;26(7):978-982. PubMed
  3. Panchal, G. M., Venkatakrishna-Bhatt, H., Doctor, R. B., and Vajpayee, S. Pharmacology of Acorus calamus L. Indian J Exp.Biol 1989;27(6):561-567.

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

Calamus Also Interacts With Other Medications

Calamus has 1,097 moderate, 19 minor known drug interactions in our database — the Felbamate one above is one of them. If you take anything else, check it against the full list below.

Moderate 1,097 Minor 19 No known interaction 1,714 (incl. Felbamate)
Taking anything else?

Check Another of Your Medications Against Calamus

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

Everything else you take

See Every Supplement That Interacts With Felbamate

This page covers Calamus only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Felbamate page lists 172 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), American Hellebore (major), Arsenic (major) and Beer (major).

By severity: 14 major · 141 moderate · 17 minor.

From our pharmacist’s overview on the Felbamate page

“Felbamate (Felbatol) is a seizure medicine usually reserved for epilepsy that other drugs have failed to control, in part because it can stress the liver on its own. That history is why its 172 supplement and herbal interactions deserve real vigilance, starting with the 14 rated major.”

Reviewed by 2 · Jul 18, 2026

Open the Felbamate interaction page

One more smart check

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

We hold 71 real supplement products containing Calamus, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Calamus. Your product may carry other ingredients that interact with Felbamate too, on top of Calamus — 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 Calamus and Felbamate 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 Calamus
Top half

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

29 days ago today
Medication Felbamate
Top half

#960 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 Calamus

What is Calamus?

Calamus
  • Digestive upset and gas
  • Loss of appetite
  • Memory and focus (traditional)
  • Coughs and colds
  • Calming or sedative effect (traditional)

Calamus is a swamp plant with a long history in Ayurvedic and traditional Chinese medicine, mostly for digestive and nervous-system complaints. However, it contains beta-asarone, a compound linked to cancer and other toxic effects in animal studies, which is why the U.S. FDA banned it from foods. Because of these safety concerns and a lack of solid human evidence, it is generally best avoided.

Read the full Calamus monograph & all interactions
Medication

About Felbamate

What Is Felbamate Used For?

Brand name: Felbatol

Felbamate is not a first-line seizure medication. It is used only when a person's epilepsy has not responded well enough to other treatments and the seizures are severe enough that the serious risks of this drug are considered acceptable.

In adults, felbamate can be used alone or alongside other antiepileptic drugs (AEDs) to treat partial seizures (seizures that start in one part of the brain), with or without spreading to become a full seizure. In children, felbamate is used as an add-on treatment for both partial and generalized seizures linked to Lennox-Gastaut syndrome, a severe form of childhood epilepsy. Felbatol is specifically labeled for these uses in both adults and children.

See full Felbamate drug information
Keep checking

Other Drugs & Calamus

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

0Major
1,097Moderate
19Minor
1,713No known interaction
1,097 Moderate 19 Minor 1,713 No interaction
Moderate

1,097 interactions

Showing 60 of 1,097 moderate interactions — see all 1,097 on the Calamus page.

Minor

19 interactions

No interaction 1,713 drugs checked — show the list

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

Showing the 60 most looked-up of 1,713 medications checked with no known interaction — see the full Calamus list.

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

Can you take Calamus with Felbamate?
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 Calamus and Felbamate 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 Felbamate and Calamus?

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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.