Herb & supplement monograph

Phellodendron Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Phellodendron interacts with medications. The heart of this page is the interaction list — every drug Phellodendron is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Phellodendron is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Reviewed by licensed pharmacists Sourced from Natural Medicines

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Phellodendron Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Phellodendron drug interaction appears low for most people, even though the list of possible interactions is long. None of the listed interactions are rated major, and nearly all are theoretical concerns tied to berberine, a compound in phellodendron bark.

Interactions deserving the most attention

The best-supported concerns involve transplant medicines: in one reported patient, berberine sharply raised blood levels of tacrolimus, and early human research suggests it may also slow the clearance of cyclosporine. Because berberine has lowered blood sugar in human studies, phellodendron could add to the effect of diabetes medications, including metformin. Additive effects on blood pressure, bleeding risk, and sedation are also possible, but these are based mostly on lab or animal findings.

What the rest of the list means

Most of this long list comes from one shared idea: berberine may slow enzymes the body uses to clear many common medications, which could raise their levels. Almost all of these interactions are predicted from lab, animal, or small preliminary studies rather than proven in people, so appearing on the list does not mean a combination will actually cause harm.

Check your medications against Phellodendron

Based on HelloPharmacist’s Phellodendron interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Phellodendron

1162 medications have a known interaction with Phellodendron, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Phellodendron using our pharmacist-reviewed interaction data.

AI summaries are generated from our Phellodendron interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction 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.
Possible. 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
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Phellodendron combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Phellodendron affects

Every type of medication (drug category) Phellodendron is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 14 drug categories Phellodendron interacts with

Anticoagulant/antiplatelet DrugsAntidiabetes DrugsAntihypertensive DrugsCns DepressantsCyclosporine (neoral, Sandimmune)Cytochrome P450 2c9 (cyp2c9) SubstratesCytochrome P450 2d6 (cyp2d6) SubstratesCytochrome P450 3a4 (cyp3a4) SubstratesDextromethorphan (robitussin Dm, Others)Losartan (cozaar)Metformin (glucophage)Midazolam (versed)Pentobarbital (nembutal)Tacrolimus (prograf)

Anticoagulant/Antiplatelet Drugs

Theoretically, phellodendron might increase the risk of bleeding when used with anticoagulant or antiplatelet drugs.
Phellodendron contains berberine. In vitro and in vivo research suggest that berberine can inhibit platelet aggregation. Theoretically, phellodendron might also inhibit platelet aggregation.