Drug & supplement interaction

European Barberry + Amantadine

Amantadine brand names: Symmetrel, Gocovri, Osmolex ER.

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

European Barberry has a moderate interaction with Amantadine. Theoretically, taking European barberry with anticholinergic drugs might cause additive effects.

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

European Barberry and Amantadine

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

Moderate

ANTICHOLINERGIC DRUGS

Why this applies to Amantadine

Amantadine falls under ANTICHOLINERGIC DRUGS — the group European Barberry interacts with.

Theoretically, taking European barberry with anticholinergic drugs might cause additive effects.
In vitro evidence suggests that European barberry might have anticholinergic properties.
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 amantadine and European barberry. Amantadine has some mild anticholinergic activity of its own, meaning it can cause things like dry mouth, blurred vision, constipation, trouble urinating, or feeling confused or dizzy, especially in older folks. In lab (test tube) studies, barberry has shown its own anticholinergic-like effects. So the theory is that pairing them could add up and make those side effects a bit more noticeable.

I want to be honest about the strength here: this is a theoretical concern based on lab data, not real-world reports of people running into trouble. It's not a reason to panic. Still, if you're taking amantadine and thinking about a concentrated barberry or berberine supplement, run it by your pharmacist or doctor first so they can keep an eye on those anticholinergic symptoms.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Shamsa F, Ahmadiani A, Khosrokhavar R. Antihistaminic and anticholinergic activity of barberry fruit (Berberis vulgaris) in the guinea-pig ileum. J Ethnopharmacol 1999;64:161-6. 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

European Barberry Also Interacts With Other Medications

European Barberry has 1,211 moderate known drug interactions in our database — the Amantadine one above is one of them. If you take anything else, check it against the full list below.

Moderate 1,211 No known interaction 1,619 (incl. Amantadine)
Taking anything else?

Check Another of Your Medications Against European Barberry

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

From our Q&A

Questions About European Barberry or Amantadine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers European Barberry or Amantadine, 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 Amantadine

This page covers European Barberry only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Amantadine page lists 46 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Henbane (major), Scopolia (major), Angel's Trumpet (moderate) and Bacopa (moderate).

By severity: 3 major · 32 moderate · 11 minor.

Open the Amantadine interaction page

One more smart check

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

We hold 2 real supplement products containing European Barberry, each one broken down to its full ingredient list — and combination products often carry several ingredients besides European Barberry. Your product may carry other ingredients that interact with Amantadine too, on top of European Barberry — 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 European Barberry and Amantadine 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 European Barberry
Top 25%

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

29 days ago today
Medication Amantadine
Steady interest

#1,725 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 European Barberry

What is European Barberry?

European Barberry
  • Digestive upset
  • Antimicrobial support
  • Blood sugar support
  • Cholesterol and metabolic support
  • Skin conditions

European barberry is a shrub whose root, bark, and berries contain berberine, a bitter plant alkaloid that has been studied mostly in isolated form. Some early research on berberine is promising for blood sugar and cholesterol, but high-quality evidence for the whole barberry herb is limited. Talk with your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Read the full European Barberry monograph & all interactions
Medication

About Amantadine

What Is Amantadine Used For?

Brand names: Symmetrel, Gocovri, Osmolex ER

Standard amantadine hydrochloride products (capsules, tablets and oral solution) are used to prevent and treat influenza A virus infection. They are also used to treat parkinsonism and drug-induced extrapyramidal reactions (movement problems caused by certain medicines).

Gocovri, an extended-release capsule, is different. It is used only for Parkinson's disease: to treat dyskinesia (uncontrolled movements) in people taking levodopa-based therapy, and as an add-on to levodopa/carbidopa for “off” episodes.

See full Amantadine drug information
Keep checking

Other Drugs & European Barberry

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

0Major
1,211Moderate
0Minor
1,618No known interaction
1,211 Moderate 1,618 No interaction
Moderate

1,211 interactions

Showing 60 of 1,211 moderate interactions — see all 1,211 on the European Barberry page.

No interaction 1,618 drugs checked — show the list

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

Showing the 60 most looked-up of 1,618 medications checked with no known interaction — see the full European Barberry list.

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

Can you take European Barberry with Amantadine?
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 European Barberry and Amantadine 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 Amantadine and European Barberry?

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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.