Drug & supplement interaction

Oregon Grape + Perampanel

Perampanel brand name: Fycompa.

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

Perampanel falls into 3 drug categories that Oregon Grape can interact with; the most serious is rated moderate. Theoretically, Oregon grape might increase the sedative effects of CNS depressants.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Oregon Grape and Perampanel

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Oregon Grape interacts with whole categories of medication. Perampanel falls into 3 of those categories, so it can interact with Oregon Grape in 3 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 3

Why this applies to Perampanel

Perampanel falls under CNS DEPRESSANTS — the group Oregon Grape interacts with.

Theoretically, Oregon grape might increase the sedative effects of CNS depressants.
Animal research suggests that berberine, a constituent of Oregon grape, can have sedative 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: Perampanel (Fycompa) already tends to make people drowsy, dizzy, or foggy, especially when you first start it or move up in dose. Oregon grape contains berberine, and in animal studies that compound showed mild sedative effects. So the worry is that stacking the two could add up to more sleepiness, more wobbliness on your feet, or trouble concentrating.

I want to be honest about the evidence though. This is theoretical, based only on lab and animal research, not on real people taking both together. So I wouldn't panic. Just don't start an Oregon grape supplement without running it by your pharmacist or doctor first, and if you do, watch closely for extra drowsiness or dizziness.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Janbaz KH, Gilani AH. Studies on preventive and curative effects of berberine on chemical-induced hepatotoxicity in rodents. Fitoterapia 2000;71:25-33.. PubMed
  2. Shanbhag, S. M., Kulkarni, H. J., and Gaitonde, B. B. Pharmacological actions of berberine on the central nervous system. Jpn.J Pharmacol 1970;20(4):482-487. PubMed
  3. Peng, W. H., Hsieh, M. T., and Wu, C. R. Effect of long-term administration of berberine on scopolamine-induced amnesia in rats. Jpn J Pharmacol 1997;74(3):261-266. DOI
  4. Sabir M and Bhide NK. Study of some pharmacological actions of berberine. Ind J Physiol & Pharmac 1971;15(3):111-132.
Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

2 of 3

Perampanel also falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES.

Theoretically, Oregon grape might increase serum levels of drugs metabolized by CYP2C9.
Preliminary clinical evidence suggests that berberine, a constituent of Oregon grape, can inhibit cytochrome P450 2C9 (CYP2C9).
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 gist: your seizure medicine Perampanel is partly cleared by a liver enzyme called CYP2C9. Oregon grape contains berberine, which early evidence suggests can slow that same enzyme down. If the enzyme works slower, Perampanel may clear out of your body more slowly and build up a bit higher than expected.

What that could feel like is more of Perampanel's usual side effects, things like dizziness, drowsiness, trouble with balance, and irritability or mood changes. Keep in mind this is mostly theoretical and based on limited evidence, so it may not be a big deal for everyone. Still, because seizure control matters, I wouldn't combine them on your own. Please check with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Guo, Y., Chen, Y., Tan, Z. R., Klaassen, C. D., and Zhou, H. H. Repeated administration of berberine inhibits cytochromes P450 in humans. Eur J Clin Pharmacol 2012;68(2):213-217. PubMed
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

3 of 3

Perampanel also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, Oregon grape might increase serum levels of drugs metabolized by CYP3A4.
In vitro research and preliminary clinical evidence suggest that berberine, a constituent of Oregon grape, moderately inhibits cytochrome P450 3A4 (CYP3A4).
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: your body relies mostly on an enzyme called CYP3A4 to break down and clear perampanel (Fycompa). Berberine, the main active compound in Oregon grape, appears to slow that enzyme down a bit. If perampanel isn't cleared as fast, more of it can linger in your system, which could nudge up its usual side effects.

For perampanel, that might mean more drowsiness, dizziness, trouble with balance, or mood and irritability changes. I'll be honest, this concern is theoretical, based on how berberine behaves in the lab rather than solid human studies, so it may not amount to much. Still, with a seizure medicine I'd play it safe. Please check with your pharmacist or doctor before combining the two rather than changing anything on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Wu X, Li Q, Xin H, Yu A, Zhong M. Effects of berberine on the blood concentration of cyclosporin A in renal transplanted recipients: clinical and pharmacokinetic study. Eur J Clin Pharmacol 2005;61:567-72. PubMed
  2. Budzinski JW, Foster BC, Vandenhoek S, Arnason JT. An in vitro evaluation of human cytochrome P450 3A4 inhibition by selected commercial herbal extracts and tinctures. Phytomedicine 2000;7:273-82. PubMed
  3. Guo, Y., Chen, Y., Tan, Z. R., Klaassen, C. D., and Zhou, H. H. Repeated administration of berberine inhibits cytochromes P450 in humans. Eur J Clin Pharmacol 2012;68(2):213-217. PubMed
  4. Hermann, R. and von, Richter O. Clinical evidence of herbal drugs as perpetrators of pharmacokinetic drug interactions. Planta Med 2012;78(13):1458-1477. 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

Oregon Grape Also Interacts With Other Medications

Oregon Grape has 1,217 moderate known drug interactions in our database — the Perampanel one above is among them. If you take anything else, check it against the full list below.

Moderate 1,217 No known interaction 1,613 (incl. Perampanel)
Taking anything else?

Check Another of Your Medications Against Oregon Grape

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

Everything else you take

See Every Supplement That Interacts With Perampanel

This page covers Oregon Grape only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Perampanel page lists 230 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: 9 major · 175 moderate · 46 minor.

From our pharmacist’s overview on the Perampanel page

“Perampanel (Fycompa) is a seizure medicine that already causes drowsiness and dizziness on its own, which is why I treat this list of 230 interacting supplements with real care. Most entries do one of two things: they add to its sedating effect, as alcohol and kava do, or they change how the liver handles it.”

Reviewed by 2 · Jul 18, 2026

Open the Perampanel interaction page

One more smart check

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

We hold 740 real supplement products containing Oregon Grape, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Oregon Grape. Your product may carry other ingredients that interact with Perampanel too, on top of Oregon Grape — 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 Oregon Grape and Perampanel 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 Oregon Grape
Top 25%

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

29 days ago today
Medication Perampanel
Steady interest

#2,031 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 Oregon Grape

What is Oregon Grape?

Oregon Grape
  • Psoriasis (topical)
  • Eczema and other skin conditions
  • Digestive upset
  • Mild skin infections
  • General 'detox' or tonic use

Oregon grape is a shrub whose root contains berberine and related compounds. The strongest (though still modest) evidence is for topical creams that may slightly ease psoriasis; evidence for other uses is limited. Talk with your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Read the full Oregon Grape monograph & all interactions
Medication

About Perampanel

What Is Perampanel Used For?

Brand name: Fycompa

Perampanel — available as Fycompa and in generic forms — is used to treat partial-onset seizures (seizures that start in one area of the brain) in patients with epilepsy aged 4 years and older. Both the tablet and oral suspension forms carry this indication.

Perampanel tablets and oral suspension are also approved as add-on (adjunctive) therapy for primary generalized tonic-clonic seizures (grand mal seizures involving the whole brain at once) in patients with epilepsy aged 12 years and older. Fycompa oral suspension and tablet share both indications.

See full Perampanel drug information
Keep checking

Other Drugs & Oregon Grape

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

0Major
1,217Moderate
0Minor
1,612No known interaction
1,217 Moderate 1,612 No interaction
Moderate

1,217 interactions

Showing 60 of 1,217 moderate interactions — see all 1,217 on the Oregon Grape page.

No interaction 1,612 drugs checked — show the list

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

Showing the 60 most looked-up of 1,612 medications checked with no known interaction — see the full Oregon Grape list.

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

Can you take Oregon Grape with Perampanel?
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 3 interactions listed for Oregon Grape and Perampanel?
Perampanel belongs to more than one drug category, and Oregon Grape 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 Oregon Grape and Perampanel 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 Perampanel and Oregon Grape?

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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.