Drug & supplement interaction

Pinellia Ternata + 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 Pinellia Ternata can interact with; the most serious is rated moderate. Evidence from animal research shows that a Pinellia ternata preparation decreases activity and increases sleeping time.

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

Pinellia Ternata and Phenobarbital, Phenytoin

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

Why Are There 2 Interactions?

Pinellia Ternata interacts with whole categories of medication. Phenobarbital, Phenytoin falls into 2 of those categories, so it can interact with Pinellia Ternata 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 Pinellia Ternata interacts with.

Evidence from animal research shows that a Pinellia ternata preparation decreases activity and increases sleeping time. Theoretically, Pinellia ternata can potentiate the therapeutic effect of CNS depressants. Some of these medications include antihistamines, barbiturates, benzodiazepines, tricyclic antidepressants, 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

This combo medication pairs phenobarbital and phenytoin, both used to control seizures. Phenobarbital is a barbiturate that calms the brain, so it has a built-in sedating effect. The concern here is fairly simple: in animal studies, Pinellia ternata made the animals less active and made them sleep longer. So in theory, layering it on top of phenobarbital could add to the drowsiness, leaving you feeling extra sleepy, foggy, dizzy, or slowed down.

I'll be honest with you, though: this is only laboratory and animal evidence, not proof in people, so it's more of a caution than a sure thing. Since phenytoin needs steady levels to work right, I wouldn't want you adding any herb without checking first. Please run it by your doctor or pharmacist before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Lin S, Nie B, Yao G, Yang H, Ye R, Yuan Z. Pinellia ternata (Thunb.) makino preparation promotes sleep by increasing REM sleep. Nat Prod Res. 2019;33(22):3326-3329. PubMed
Moderate

BARBITURATES

2 of 2

Phenobarbital, Phenytoin also falls under BARBITURATES.

Evidence from animal research shows that a Pinellia ternata preparation decreases activity and increases sleeping time. Theoretically, Pinellia ternata can potentiate the therapeutic effect of barbiturates. Some of these sedative medications include pentobarbital (Nembutal), phenobarbital (Luminal), secobarbital (Seconal), 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 gist for the phenobarbital part of this combo product. Phenobarbital is a barbiturate, and it works by calming down your nervous system. In animal studies, a Pinellia ternata preparation made the animals less active and made them sleep longer. So the worry is that this herb could add to phenobarbital's sedating effects, leaving you groggier, more drowsy, dizzy, or slow to react than you'd expect.

I want to be honest about the evidence, though: this is based only on animal research, not people, so it's more of a theoretical concern than something proven. Still, since phenobarbital already makes folks sleepy, I'd rather you not stack the two without checking first. Please talk with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Lin S, Nie B, Yao G, Yang H, Ye R, Yuan Z. Pinellia ternata (Thunb.) makino preparation promotes sleep by increasing REM sleep. Nat Prod Res. 2019;33(22):3326-3329. 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

Pinellia Ternata Also Interacts With Other Medications

Pinellia Ternata has 255 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 255 No known interaction 2,575 (incl. Phenobarbital, Phenytoin)
Taking anything else?

Check Another of Your Medications Against Pinellia Ternata

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

Everything else you take

See Every Supplement That Interacts With Phenobarbital, Phenytoin

This page covers Pinellia Ternata 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

One more smart check

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

We hold 20 real supplement products containing Pinellia Ternata, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Pinellia Ternata. Your product may carry other ingredients that interact with Phenobarbital, Phenytoin too, on top of Pinellia Ternata — 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 Pinellia Ternata 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 Pinellia Ternata
Steady interest

#1,036 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Phenobarbital, Phenytoin
Steady interest

#2,193 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 Pinellia Ternata

What is Pinellia Ternata?

  • Nausea and vomiting
  • Cough with phlegm
  • Morning sickness (traditional use)
  • Digestive upset and bloating
  • Throat discomfort

Pinellia ternata is a tuber used in traditional Chinese medicine, most often for nausea, vomiting, and phlegmy coughs, and almost always as part of multi-herb formulas. The raw plant is toxic and must be specially processed before use, so it should only be used under qualified guidance. Solid human evidence is limited, and it should be avoided in pregnancy and breastfeeding.

Read the full Pinellia Ternata monograph & all interactions
Keep checking

Other Drugs & Pinellia Ternata

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

0Major
255Moderate
0Minor
2,574No known interaction
255 Moderate 2,574 No interaction
Moderate

255 interactions

Showing 60 of 255 moderate interactions — see all 255 on the Pinellia Ternata page.

No interaction 2,574 drugs checked — show the list

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

Showing the 60 most looked-up of 2,574 medications checked with no known interaction — see the full Pinellia Ternata list.

See the full Pinellia Ternata 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
Pinellia Ternata 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 Pinellia Ternata and Phenobarbital, Phenytoin Together: Common Questions

Can you take Pinellia Ternata 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 Pinellia Ternata and Phenobarbital, Phenytoin?
Phenobarbital, Phenytoin belongs to more than one drug category, and Pinellia Ternata 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 Pinellia Ternata 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.