Drug & supplement interaction

Rabdosia Rubescens + Tucatinib

Tucatinib brand name: Tukysa.

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

Tucatinib falls into 2 drug categories that Rabdosia Rubescens can interact with; the most serious is rated moderate. Rabdosia rubescens might increase levels of p-glycoprotein substrates.

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

Rabdosia Rubescens and Tucatinib

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

Why Are There 2 Interactions?

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

Moderate

P-GLYCOPROTEIN SUBSTRATES

1 of 2

Why this applies to Tucatinib

Tucatinib falls under P-GLYCOPROTEIN SUBSTRATES — the group Rabdosia Rubescens interacts with.

Rabdosia rubescens might increase levels of p-glycoprotein substrates. In vitro research shows that Rabdosia rubescens extract inhibits p-glycoprotein levels and activity. Drugs that might be affected include some chemotherapeutic agents (doxorubicin, etoposide, paclitaxel, vinblastine, vincristine, vindesine), antifungals (ketoconazole, itraconazole), protease inhibitors (amprenavir, indinavir, nelfinavir, saquinavir), H2 antagonists (cimetidine, ranitidine), some calcium channel blockers (diltiazem, verapamil), digoxin, corticosteroids, erythromycin, cisapride (Propulsid), fexofenadine (Allegra), cyclosporine, loperamide (Imodium), quinidine, and others.
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 quick version: Tucatinib (Tukysa) is moved around your body partly by a transporter called P-glycoprotein, which acts like a pump that helps push the drug out of cells. Lab research suggests Rabdosia rubescens may slow that pump down. If that pump works less, more tucatinib could stay in your system, which in theory could mean stronger effects and a higher chance of side effects like diarrhea, nausea, hand-foot soreness, fatigue, or changes in liver blood tests.

That said, this is based only on test-tube studies, not on real patients, so we don't truly know how much it matters in people. Tucatinib is already serious cancer therapy, so please don't add this herb on your own. Run it by your oncologist or pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Li F, Fan J, Wu Z, et al. Reversal effects of Rabdosia rubescens extract on multidrug resistance of MCF-7/Adr cells in vitro. Pharm Biol. 2013;51(9):1196-203.
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 2

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

In vitro research shows that oridonin, a constituent of Rabdosia rubescens, induces cytochrome P450 3A4 (CYP3A4) enzyme. Also, in an animal model, oridonin induces a gene homologous to CYP3A4. So far, this interaction has not been reported in humans. However, watch for a decrease in the levels of drugs metabolized by CYP3A4 in patients taking Rabdosia rubescens. Some drugs metabolized by CYP3A4 that might be affected are some benzodiazepines such as alprazolam (Xanax), diazepam (Valium), midazolam (Versed), triazolam (Halcion); calcium channel blockers such as amlodipine (Norvasc), diltiazem (Cardizem, Dilacor, others), felodipine (Plendil), verapamil (Calan, Verelan, others); cyclosporine (Neoral, Sandimmune); some HIV antivirals such as indinavir (Crixivan), ritonavir (Norvir), saquinavir (Fortovase, Invirase); some HMG CoA reductase inhibitors such as atorvastatin (Lipitor), lovastatin (Mevacor); some macrolide antibiotics such as erythromycin and clarithromycin (Biaxin); quinidine; and many others.
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 concern with pairing Rabdosia rubescens with your Tucatinib (Tukysa). Tucatinib is an active cancer drug that your liver clears using an enzyme called CYP3A4. Lab studies suggest oridonin, a compound in this herb, may speed that enzyme up. If that happens in people, your body could break down tucatinib faster and leave less of it working against your cancer.

That matters here because tucatinib is part of a carefully dosed cancer treatment, and you don't want it quietly losing strength. The honest caveat: this is only test-tube and animal data, never confirmed in humans, so it's a theoretical worry, not a proven one. Still, with a cancer medication I'd play it safe. Please run any supplement past your oncologist or pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction

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

Rabdosia Rubescens Also Interacts With Other Medications

Rabdosia Rubescens has 713 moderate, 69 minor known drug interactions in our database — the Tucatinib one above is among them. If you take anything else, check it against the full list below.

Moderate 713 Minor 69 No known interaction 2,048 (incl. Tucatinib)
Taking anything else?

Check Another of Your Medications Against Rabdosia Rubescens

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

Everything else you take

See Every Supplement That Interacts With Tucatinib

This page covers Rabdosia Rubescens only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tucatinib page lists 178 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Grapefruit (major), Siberian Cocklebur (major) and St. John's Wort (major).

By severity: 6 major · 137 moderate · 35 minor.

From our pharmacist’s overview on the Tucatinib page

“Anyone taking tucatinib (Tukysa) for HER2-positive breast cancer should treat this page with genuine care, because the drug leaves little room for surprises. Most entries change how much tucatinib the body absorbs or clears, since it moves through the CYP3A4 enzyme pathway.”

Reviewed by 2 · Jul 18, 2026

Open the Tucatinib interaction page

How much people look this up

Where Rabdosia Rubescens and Tucatinib 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 Rabdosia Rubescens
Steady interest

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

29 days ago today
Medication Tucatinib
Steady interest

#1,635 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 Rabdosia Rubescens

What is Rabdosia Rubescens?

Rabdosia Rubescens
  • Sore throat and respiratory complaints
  • Inflammation
  • Antimicrobial support
  • Digestive complaints
  • Traditional cancer support

Rabdosia rubescens is a Chinese herb traditionally used for sore throats, inflammation, and infections, and its compound oridonin has drawn lab interest for possible anticancer effects. However, strong human evidence is lacking for any use, and safety has not been well studied, so talk with your pharmacist or doctor before trying it.

Read the full Rabdosia Rubescens monograph & all interactions
Medication

About Tucatinib

What Is Tucatinib Used For?

Brand name: Tukysa

Tukysa (tucatinib) tablets are used in combination with trastuzumab and capecitabine to treat adults with advanced, unresectable, or metastatic HER2-positive breast cancer — including those whose cancer has spread to the brain — who have already received at least one HER2-targeted treatment.

Tukysa tablets are also used in combination with trastuzumab alone to treat adults with RAS wild-type, HER2-positive unresectable or metastatic colorectal cancer that has continued to grow after prior chemotherapy. This colorectal cancer use has received accelerated approval, meaning final approval depends on further study results confirming the benefit.

See full Tucatinib drug information
Keep checking

Other Drugs & Rabdosia Rubescens

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

0Major
713Moderate
69Minor
2,047No known interaction
713 Moderate 69 Minor 2,047 No interaction
Moderate

713 interactions

Showing 60 of 713 moderate interactions — see all 713 on the Rabdosia Rubescens page.

Minor

69 interactions

Showing 60 of 69 minor interactions — see all 69 on the Rabdosia Rubescens page.

No interaction 2,047 drugs checked — show the list

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

Showing the 60 most looked-up of 2,047 medications checked with no known interaction — see the full Rabdosia Rubescens list.

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

Can you take Rabdosia Rubescens with Tucatinib?
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 Rabdosia Rubescens and Tucatinib?
Tucatinib belongs to more than one drug category, and Rabdosia Rubescens 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 Rabdosia Rubescens and Tucatinib 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

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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.