Drug & supplement interaction

Rabdosia Rubescens + Phenobarbital, Phenytoin

Phenobarbital, Phenytoin brand name: Dilantin with PB.

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

Rabdosia Rubescens has a minor interaction with Phenobarbital, Phenytoin. In vitro research shows that oridonin, a constituent of Rabdosia rubescens, induces cytochrome P450 2C9 (CYP2C9) enzyme.

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

Rabdosia Rubescens and Phenobarbital, Phenytoin

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

Minor

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

Why this applies to Phenobarbital, Phenytoin

Phenobarbital, Phenytoin falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES — the group Rabdosia Rubescens interacts with.

In vitro research shows that oridonin, a constituent of Rabdosia rubescens, induces cytochrome P450 2C9 (CYP2C9) enzyme. So far, this interaction has not been reported in humans. However, watch for a decrease in the levels of drugs metabolized by CYP2C9 in patients taking Rabdosia rubescens. Some drugs metabolized by CYP2C9 include nonsteroidal anti-inflammatory drugs (NSAIDs) such as diclofenac (Cataflam, Voltaren), ibuprofen (Motrin), meloxicam (Mobic), and piroxicam (Feldene); celecoxib (Celebrex); amitriptyline (Elavil); warfarin (Coumadin); glipizide (Glucotrol); losartan (Cozaar); and others.
Severity Minor 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 your seizure medicine. Phenobarbital and phenytoin are both partly cleared by a liver enzyme called CYP2C9. Lab research suggests a compound in Rabdosia rubescens (oridonin) may speed up that enzyme. In theory, that could push your drug levels a bit lower, and for phenytoin especially, which has a narrow safe range, lower levels could mean breakthrough seizures or shakier seizure control.

I want to be honest about how thin this evidence is. It comes only from test-tube studies and has never been seen in real patients, so the rating is minor. Still, because these are seizure medicines where small swings matter, please loop in your pharmacist or doctor before adding this herb rather than starting it on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Zhang YW, Zheng XW, Liu YJ, et al. Effect of oridonin on cytochrome P450 expression and activities in HepaRG Cell. Pharmacology. 2018;101(5-6):246-254. 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

Rabdosia Rubescens Also Interacts With Other Medications

Rabdosia Rubescens has 714 moderate, 68 minor known drug interactions in our database — the Phenobarbital, Phenytoin one above is one of them. If you take anything else, check it against the full list below.

Moderate 714 Minor 68 No known interaction 2,048 (incl. Phenobarbital, Phenytoin)
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 Phenobarbital, Phenytoin

This page covers Rabdosia Rubescens only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phenobarbital, Phenytoin page lists 229 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Kava (major).

By severity: 9 major · 192 moderate · 28 minor.

From our pharmacist’s overview on the Phenobarbital, Phenytoin page

“If your seizure medicine is the phenobarbital and phenytoin combination (Dilantin with PB), read this list carefully before you add any supplement. Nine of the 229 entries rate major, and most of the risk runs through two channels.”

Reviewed by 2 · Jul 18, 2026

Open the Phenobarbital, Phenytoin interaction page

How much people look this up

Where Rabdosia Rubescens and Phenobarbital, Phenytoin 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

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

29 days ago today
Medication Phenobarbital, Phenytoin
Top 25%

#537 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
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
714Moderate
68Minor
2,047No known interaction
714 Moderate 68 Minor 2,047 No interaction
Moderate

714 interactions

Showing 60 of 714 moderate interactions — see all 714 on the Rabdosia Rubescens page.

Minor

68 interactions

Showing 60 of 68 minor interactions — see all 68 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 Phenobarbital, Phenytoin, 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 Phenobarbital, Phenytoin supplement interactions › Every supplement checked against Phenobarbital, Phenytoin, ranked by severity 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 Phenobarbital, Phenytoin Together: Common Questions

Can you take Rabdosia Rubescens with Phenobarbital, Phenytoin?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Rabdosia Rubescens and Phenobarbital, Phenytoin interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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.