Drug & supplement interaction

Breadfruit + Phenobarbital, Phenytoin

Phenobarbital, Phenytoin brand name: Dilantin with PB.

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

Breadfruit has a moderate interaction with Phenobarbital, Phenytoin. Breadfruit might increase the levels of drugs metabolized by cytochrome P450 2C8 (CYP2C8) enzymes.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Breadfruit and Phenobarbital, Phenytoin

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

Moderate

CYTOCHROME P450 2C8 (CYP2C8) SUBSTRATES

Why this applies to Phenobarbital, Phenytoin

Phenobarbital, Phenytoin falls under CYTOCHROME P450 2C8 (CYP2C8) SUBSTRATES — the group Breadfruit interacts with.

Breadfruit might increase the levels of drugs metabolized by cytochrome P450 2C8 (CYP2C8) enzymes. So far, this interaction has not been reported in humans. However, in vitro evidence shows that the breadfruit constituent artocarpin inhibits CYP2C8 enzymes, which might increase the levels of CYP2C8 substrates. Some drugs metabolized by CYP2C8 include amiodarone (Cardarone), paclitaxel (Taxol); nonsteroidal anti-inflammatory drugs (NSAIDs) such as diclofenac (Voltaren) and ibuprofen (Motrin), rosiglitazone (Avandia), 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 honest picture: the concern on file is that a compound in breadfruit (artocarpin) might block a liver enzyme called CYP2C8, which could let certain drugs build up. But this comes only from lab dish studies, not from people, so it's quite theoretical. On top of that, both phenytoin and phenobarbital are cleared mainly by other enzymes (phenytoin through CYP2C9 and CYP2C19, phenobarbital largely through CYP2C19 and direct elimination), so CYP2C8 isn't their main pathway anyway.

That said, both of these are narrow therapeutic index drugs, meaning small level changes can matter, causing drowsiness, dizziness, unsteady walking, or slurred speech if levels climb. Eating breadfruit as food is very unlikely to cause trouble. Before using concentrated leaf teas or extracts, check with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Qu W, Liu X. Identification of cytochrome P450 isoforms involved in the metabolism of artocarpin and assessment of its drug-drug interaction. Biomed Chromatogr. 2018;32(4). 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

Breadfruit Also Interacts With Other Medications

Breadfruit has 437 moderate, 504 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 437 Minor 504 No known interaction 1,889 (incl. Phenobarbital, Phenytoin)
Taking anything else?

Check Another of Your Medications Against Breadfruit

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

Everything else you take

See Every Supplement That Interacts With Phenobarbital, Phenytoin

This page covers Breadfruit 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 Breadfruit 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 Breadfruit
Top half

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

29 days ago today
Medication Phenobarbital, Phenytoin
Top 25%

#657 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 Breadfruit

What is Breadfruit?

  • Source of nutrition and energy
  • High blood pressure
  • Diabetes and blood sugar support
  • Inflammation and joint discomfort
  • Skin conditions

Breadfruit is a starchy tropical fruit eaten as a staple food, and its leaves are used in traditional medicine for conditions like high blood pressure and diabetes. As a food it is nutritious and generally safe, but the medicinal use of leaf teas or extracts has very little human research to back it up. Talk with your pharmacist or doctor before using breadfruit products for a health condition.

Read the full Breadfruit monograph & all interactions
Keep checking

Other Drugs & Breadfruit

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

0Major
437Moderate
504Minor
1,888No known interaction
437 Moderate 504 Minor 1,888 No interaction
Moderate

437 interactions

Showing 60 of 437 moderate interactions — see all 437 on the Breadfruit page.

Minor

504 interactions

Showing 60 of 504 minor interactions — see all 504 on the Breadfruit page.

No interaction 1,888 drugs checked — show the list

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

Showing the 60 most looked-up of 1,888 medications checked with no known interaction — see the full Breadfruit list.

See the full Breadfruit 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
Breadfruit 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 Breadfruit and Phenobarbital, Phenytoin Together: Common Questions

Can you take Breadfruit 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.
How serious is the Breadfruit 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

Still Have a Question About Phenobarbital, Phenytoin and Breadfruit?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.