Drug & supplement interaction

Corydalis Yanhusuo + Phenobarbital, Phenytoin

Phenobarbital, Phenytoin brand name: Dilantin with PB.

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

Phenobarbital, Phenytoin falls into 2 drug categories that Corydalis Yanhusuo can interact with; the most serious is rated moderate. Theoretically, Corydalis yanhusuo might increase the sedative effects of CNS depressants.

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

Corydalis Yanhusuo and Phenobarbital, Phenytoin

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

Why Are There 2 Interactions?

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

Moderate

CNS DEPRESSANTS

1 of 2

Why this applies to Phenobarbital, Phenytoin

Phenobarbital, Phenytoin falls under CNS DEPRESSANTS — the group Corydalis Yanhusuo interacts with.

Theoretically, Corydalis yanhusuo might increase the sedative effects of CNS depressants.
Corydalis yanhusuo contains berberine. Animal research suggests that berberine may have sedative effects. Theoretically, Corydalis yanhusuo might also have CNS depressants 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 simple version: this combination, which pairs phenobarbital and phenytoin, both work in your brain and can already make you feel sleepy or slowed down. Phenobarbital in particular is a known sedative. The concern with Corydalis yanhusuo is that some of its natural compounds may have their own calming, drowsy effect on the nervous system. Stacking the two together could, in theory, leave you more groggy than usual, with extra drowsiness, dizziness, slowed thinking, or poor coordination.

I want to be honest about the evidence though: this is theoretical, based on animal and lab studies, not solid human research. It may never cause a problem for you. Still, since phenytoin is a fussy drug to dose, please check with your pharmacist or doctor before adding this herb rather than changing anything yourself.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Janbaz KH, Gilani AH. Studies on preventive and curative effects of berberine on chemical-induced hepatotoxicity in rodents. Fitoterapia 2000;71:25-33.. PubMed
  2. Shanbhag, S. M., Kulkarni, H. J., and Gaitonde, B. B. Pharmacological actions of berberine on the central nervous system. Jpn.J Pharmacol 1970;20(4):482-487. PubMed
  3. Peng, W. H., Hsieh, M. T., and Wu, C. R. Effect of long-term administration of berberine on scopolamine-induced amnesia in rats. Jpn J Pharmacol 1997;74(3):261-266. DOI
  4. Sabir M and Bhide NK. Study of some pharmacological actions of berberine. Ind J Physiol & Pharmac 1971;15(3):111-132.
Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

2 of 2

Phenobarbital, Phenytoin also falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES.

Theoretically, Corydalis yanhusuo might increase serum levels of drugs metabolized by CYP2C9.
Corydalis yanhusuo contains berberine. Preliminary clinical research shows that berberine can inhibit CYP2C9. Theoretically, Corydalis yanhusuo might also inhibit CYP2C9.
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 your seizure medicine. Phenytoin is cleared from the body partly by a liver enzyme called CYP2C9. Corydalis contains berberine, which lab and early human research suggests can slow down that same enzyme. If it does, your phenytoin could clear more slowly and build up in your blood.

Phenytoin has a very narrow safe range, so even small shifts can matter. Too much can cause dizziness, slurred speech, wobbly walking, double vision, drowsiness, or nausea. Phenobarbital can add extra sleepiness. To be fair, this concern is theoretical and not proven in people, so don't panic. Just don't add Corydalis without checking with your pharmacist or doctor first, since they may want to watch your levels.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Guo, Y., Chen, Y., Tan, Z. R., Klaassen, C. D., and Zhou, H. H. Repeated administration of berberine inhibits cytochromes P450 in humans. Eur J Clin Pharmacol 2012;68(2):213-217. 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

Corydalis Yanhusuo Also Interacts With Other Medications

Corydalis Yanhusuo has 1,159 moderate known drug interactions in our database — the Phenobarbital, Phenytoin one above is among them. If you take anything else, check it against the full list below.

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

Check Another of Your Medications Against Corydalis Yanhusuo

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

Everything else you take

See Every Supplement That Interacts With Phenobarbital, Phenytoin

This page covers Corydalis Yanhusuo 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 Corydalis Yanhusuo 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 Corydalis Yanhusuo
Steady interest

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

29 days ago today
Medication Phenobarbital, Phenytoin
Steady interest

#1,984 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 Corydalis Yanhusuo

What is Corydalis Yanhusuo?

  • Pain relief
  • Menstrual cramps
  • Headache
  • Stress and sleep support
  • Stomach and abdominal discomfort

Corydalis yanhusuo is a traditional Chinese herb used mainly for pain. Some early laboratory and animal research suggests its compounds may affect pain and the nervous system, but high-quality human studies are limited, so its true benefits and long-term safety are not well established. Talk with your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Read the full Corydalis Yanhusuo monograph & all interactions
Keep checking

Other Drugs & Corydalis Yanhusuo

Browse every other medication we’ve checked against Corydalis Yanhusuo — 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 Corydalis Yanhusuo page.

No interaction 1,670 drugs checked — show the list

We also checked Corydalis Yanhusuo 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 Corydalis Yanhusuo list.

See the full Corydalis Yanhusuo 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
Corydalis Yanhusuo 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 Corydalis Yanhusuo and Phenobarbital, Phenytoin Together: Common Questions

Can you take Corydalis Yanhusuo with Phenobarbital, Phenytoin?
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 Corydalis Yanhusuo and Phenobarbital, Phenytoin?
Phenobarbital, Phenytoin belongs to more than one drug category, and Corydalis Yanhusuo 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 Corydalis Yanhusuo and Phenobarbital, Phenytoin 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.