Drug & supplement interaction

Phellodendron + Olmesartan Medoxomil

Olmesartan Medoxomil brand names: Olmesartan Medoxomil, Benicar.

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

Phellodendron has a moderate interaction with Olmesartan Medoxomil. Theoretically, phellodendron might have additive effects with antihypertensive drugs.

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

Phellodendron and Olmesartan Medoxomil

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

Moderate

ANTIHYPERTENSIVE DRUGS

Why this applies to Olmesartan Medoxomil

Olmesartan Medoxomil falls under ANTIHYPERTENSIVE DRUGS — the group Phellodendron interacts with.

Theoretically, phellodendron might have additive effects with antihypertensive drugs.
Phellodendron contains berberine. Animal research suggests that berberine can have hypotensive effects. Also, a clinical study suggests that taking berberine in combination with amlodipine can lower systolic and diastolic blood pressure when compared with amlodipine alone. Theoretically, phellodendron might also reduce blood pressure.
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: Olmesartan (Benicar) already lowers your blood pressure by relaxing your blood vessels. Phellodendron contains berberine, which in animal studies and one small human trial seemed to nudge blood pressure down too. So if you take them together, the worry is they could stack up and drop your pressure a bit more than expected.

If that happened, you might feel lightheaded, dizzy, tired, or wobbly when you stand up quickly. To be clear, this is a theoretical concern based mostly on how berberine behaves, not strong proof it will happen to you. It's still worth a quick chat with your pharmacist or doctor, especially if your readings already run low. Please don't start or stop anything on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sabir M and Bhide NK. Study of some pharmacological actions of berberine. Ind J Physiol & Pharmac 1971;15(3):111-132.
  2. Chun YT, Yip TT, Lau KL, and et al. A biochemical study on the hypotensive effect of berberine in rats. Gen Pharmac 1979;10:177-182. PubMed
  3. Lan J, Zhao Y, Dong F, et al. Meta-analysis of the effect and safety of berberine in the treatment of type 2 diabetes mellitus, hyperlipemia and hypertension. J Ethnopharmacol. 2015;161:69-81. 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

Phellodendron Also Interacts With Other Medications

Phellodendron has 1,159 moderate known drug interactions in our database — the Olmesartan Medoxomil one above is one of them. If you take anything else, check it against the full list below.

Moderate 1,159 No known interaction 1,671 (incl. Olmesartan Medoxomil)
Taking anything else?

Check Another of Your Medications Against Phellodendron

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

From our Q&A

Questions About Phellodendron or Olmesartan Medoxomil

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

This page covers Phellodendron only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Olmesartan Medoxomil page lists 136 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), Tyramine (major) and Adrafinil (moderate).

By severity: 4 major · 111 moderate · 21 minor.

From our pharmacist’s overview on the Olmesartan Medoxomil page

“Olmesartan medoxomil (Benicar) lowers blood pressure by relaxing blood vessels, and nearly everything on this page, 119 of the 136 ingredients, pulls on that same lever, deepening the drop or working against it. Four entries rate major, which is why this list deserves genuine care rather than a quick skim.”

Reviewed by 2 · Jul 18, 2026

Open the Olmesartan Medoxomil interaction page

One more smart check

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

We hold 393 real supplement products containing Phellodendron, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Phellodendron. Your product may carry other ingredients that interact with Olmesartan Medoxomil too, on top of Phellodendron — 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 Phellodendron and Olmesartan Medoxomil 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 Phellodendron
Top 25%

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

29 days ago today
Medication Olmesartan Medoxomil
Top half

#1,229 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 Phellodendron

What is Phellodendron?

Phellodendron
  • Digestive complaints and diarrhea
  • Inflammation and joint discomfort
  • Stress and weight management (in combination products)
  • Skin conditions (topical, traditional)
  • Antimicrobial support

Phellodendron is a traditional Chinese medicine bark (Huang Bai) that contains berberine and other plant compounds with antimicrobial and anti-inflammatory activity in lab studies. Human evidence for most uses is limited, and it is often sold in combination with other herbs, making its individual effects hard to judge. Talk with your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Read the full Phellodendron monograph & all interactions
Medication

About Olmesartan

What Is Olmesartan Used For?

Brand names: Olmesartan Medoxomil, Benicar

Olmesartan treats high blood pressure (hypertension) in adults and in children aged 6 years and older. It can be used alone or combined with other blood pressure medicines. Lowering blood pressure reduces the risk of serious events like stroke and heart attack.

It is available as Benicar and as generic olmesartan medoxomil tablets, including a combination tablet with hydrochlorothiazide. All of these products are used for high blood pressure.

See full Olmesartan drug information
Keep checking

Other Drugs & Phellodendron

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

0Major
1,159Moderate
0Minor
1,670No known interaction
1,159 Moderate 1,670 No interaction
Moderate

1,159 interactions

Showing 60 of 1,159 moderate interactions — see all 1,159 on the Phellodendron page.

No interaction 1,670 drugs checked — show the list

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

Showing the 60 most looked-up of 1,670 medications checked with no known interaction — see the full Phellodendron list.

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

Can you take Phellodendron with Olmesartan Medoxomil?
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 Phellodendron and Olmesartan Medoxomil 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 Olmesartan Medoxomil and Phellodendron?

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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.