Drug & supplement interaction

Breadfruit + Phenytoin

Phenytoin brand names: Dilantin Kapseals, Dilantin, Di-Phen, Dilantin Infatabs, Phenytek, and others.

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

Breadfruit has a moderate interaction with 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 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 Phenytoin

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 gist for you. The concern on file is that a compound in breadfruit (called artocarpin) may slow down a liver enzyme called CYP2C8. If that enzyme works more slowly, drugs it clears can build up. Phenytoin is not a prodrug, so in theory higher levels would mean stronger effects and more side effects, things like drowsiness, dizziness, unsteady walking, slurred speech, or jerky eye movements. Phenytoin is also a narrow therapeutic index medicine, meaning even small shifts in blood level can matter.

That said, this is only seen in lab dishes, never reported in real people, and phenytoin actually relies mostly on a different enzyme (CYP2C9). Eating breadfruit as food is very unlikely to be an issue. Before using concentrated leaf teas or extracts, please 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 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. 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.

From our Q&A

Questions About Breadfruit or Phenytoin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Breadfruit or Phenytoin, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Phenytoin

This page covers Breadfruit only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phenytoin page lists 224 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 · 187 moderate · 28 minor.

From our pharmacist’s overview on the Phenytoin page

“Phenytoin (Dilantin) is a seizure medicine with a narrow therapeutic index, meaning small changes in its blood level can bring seizures back or tip over into toxicity, so I treat its supplement list with real seriousness. The biggest group, 78 ingredients, piles on sedation, and alcohol, kava, and GHB all rate major for exactly that re…”

Reviewed by 2 · Jul 18, 2026

Open the Phenytoin interaction page

How much people look this up

Where Breadfruit and 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
Steady interest

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

29 days ago today
Medication Phenytoin
Steady interest

#1,761 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
Medication

About Phenytoin

What Is Phenytoin Used For?

Brand names: Dilantin Kapseals, Dilantin, Di-Phen, Dilantin Infatabs, Phenytek, Dilantin injection

Phenytoin is used to treat and prevent seizures. The specific types covered depend on the formulation. Oral extended-release capsules (including Phenytek), chewable tablets (including Dilantin Infatabs and Phenytoin Infatabs), and oral suspension (including Dilantin-125) are used for tonic-clonic (grand mal) and psychomotor (temporal lobe) seizures; most oral forms also cover prevention and treatment of seizures occurring during or after neurosurgery. Chewable tablets and some capsule formulations also cover complex partial seizures.

Parenteral (injectable) phenytoin sodium is used for generalized tonic-clonic status epilepticus (a prolonged, life-threatening seizure emergency) and for prevention and treatment of seizures during neurosurgery. The IV form can also substitute short-term for oral phenytoin when a patient cannot take it by mouth.

See full Phenytoin drug information
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 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 Phenytoin supplement interactions › Every supplement checked against Phenytoin, ranked by severity Phenytoin 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 Breadfruit and Phenytoin Together: Common Questions

Can you take Breadfruit with 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 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 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.