Drug & supplement interaction

European Barberry + Ambrisentan

Ambrisentan brand names: Letairis, Volibris.

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

Ambrisentan falls into 2 drug categories that European Barberry can interact with; the most serious is rated moderate. Theoretically, taking European barberry with antihypertensive drugs might increase the risk of hypotension.

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

European Barberry and Ambrisentan

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

Why Are There 2 Interactions?

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

Moderate

ANTIHYPERTENSIVE DRUGS

1 of 2

Why this applies to Ambrisentan

Ambrisentan falls under ANTIHYPERTENSIVE DRUGS — the group European Barberry interacts with.

Theoretically, taking European barberry with antihypertensive drugs might increase the risk of hypotension.
Animal and human research suggests that European barberry extracts can have hypotensive 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 gist: barberry (and the berberine in it) may gently lower blood pressure on its own. Ambrisentan also relaxes and widens blood vessels to ease pressure in your lungs, so stacking the two could add up and push your blood pressure a little lower than intended. That might leave you feeling dizzy, lightheaded, or faint, especially when you stand up quickly.

I'll be honest, this is a theoretical concern based mostly on how these things work in lab and animal studies, not a well-documented problem in people taking this exact combo. Still, since both can nudge blood pressure down, it's worth a quick chat with your pharmacist or doctor before adding barberry, and let them know if you notice new dizziness.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Fatehi M, Saleh TM, Fatehi-Hassanabad Z, et al. A pharmacological study on Berberis vulgaris fruit extract. J Ethnopharmacol 2005;102:46-52. PubMed
  2. Fatehi-Hassanabad, Z., Jafarzadeh, M., Tarhini, A., and Fatehi, M. The antihypertensive and vasodilator effects of aqueous extract from Berberis vulgaris fruit on hypertensive rats. Phytother Res 2005;19(3):222-225.
  3. Lazavi F, Mirmiran P, Sohrab G, Nikpayam O, Angoorani P, Hedayati M. The barberry juice effects on metabolic factors and oxidative stress in patients with type 2 diabetes: A randomized clinical trial. Complement Ther Clin Pract. 2018;31:170-174. PubMed
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 2

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

Theoretically, European barberry might increase the levels and clinical effects of CYP3A4 substrates.
There is very preliminary evidence suggesting that berberine, a constituent of European barberry, might inhibit the CYP3A4 enzyme. Theoretically, European barberry might have a similar effect.
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 for these two together. Your body relies partly on an enzyme called CYP3A4 to break down ambrisentan and clear it out. Berberine, the main active compound in European barberry, has shown a hint in early lab work that it may slow that enzyme down. If that happens, ambrisentan could linger a bit longer and build up, which might mean stronger effects and a higher chance of side effects like swelling in the legs and ankles, a stuffy or runny nose, flushing, headache, or that washed-out, low-energy feeling.

I want to be honest that this is theoretical and based on very preliminary evidence, not real patient reports, so it may not amount to much. Still, since ambrisentan is an important medication, I'd run barberry past your pharmacist or doctor before starting it rather than guessing.

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

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 Ambrisentan one above is among them. If you take anything else, check it against the full list below.

Moderate 1,211 No known interaction 1,619 (incl. Ambrisentan)
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.

Everything else you take

See Every Supplement That Interacts With Ambrisentan

This page covers European Barberry only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Ambrisentan page lists 256 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Beer (major) and Grapefruit (major).

By severity: 9 major · 210 moderate · 37 minor.

Open the Ambrisentan 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 Ambrisentan 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 Ambrisentan 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%

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

29 days ago today
Medication Ambrisentan
Top half

#989 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 Ambrisentan

What Is Ambrisentan Used For?

Brand names: Letairis, Volibris

Ambrisentan tablets and Letairis tablets are both used to treat pulmonary arterial hypertension (PAH, WHO Group 1) — a condition where the blood pressure in the arteries leading to the lungs is dangerously high. Both are approved to help adults exercise better and slow the worsening of PAH.

Both ambrisentan tablets and Letairis are also approved to be used together with tadalafil (another PAH medicine) to further reduce the risk of disease progression, lower the chance of hospitalization for worsening PAH, and improve exercise ability. Most of the clinical evidence was in patients with mild-to-moderate symptoms and PAH caused by unknown or inherited causes, or PAH linked to connective tissue diseases.

See full Ambrisentan 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 Ambrisentan, 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 Ambrisentan supplement interactions › Every supplement checked against Ambrisentan, ranked by severity Ambrisentan 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 Ambrisentan Together: Common Questions

Can you take European Barberry with Ambrisentan?
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 European Barberry and Ambrisentan?
Ambrisentan belongs to more than one drug category, and European Barberry 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 European Barberry and Ambrisentan 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 Ambrisentan 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.