Medication interaction hub

What Supplements Interact with Phenytoin?

Phenytoin brand names: Dilantin Kapseals, Dilantin, Di-Phen, Dilantin Infatabs, Phenytek, and others. Every interaction below applies to the brands too.

224 Interactions 9 Major 187 Moderate 28 Minor
Curated & coded by · Clinical Pharmacist · Updated September 22, 2026

Drug–supplement interaction data sourced from Natural Medicines Pro, the licensed clinical database from TRC Healthcare / Therapeutic Research, with additional analysis by the HelloPharmacist Pharmacist Team. Our sources · Editorial policy

What is this page for?

One answer, for one medication: what supplements and herbal products interact with Phenytoin? Every vitamin, herb, and supplement ingredient we’ve checked against it is on this page, ranked by severity, each linking to the full report for that exact pair.

This page covers supplement interactions only — to check Phenytoin against your other medications, use the drug–drug interaction checker. Educational information from our licensed clinical databases, not medical advice. Our editorial policy

HelloPharmacist Bottom Line
Our Pharmacist Explains
What is this? The interaction data in the HelloPharmacist supplement database is licensed from Natural Medicines Pro by TRC Healthcare (Therapeutic Research). HelloPharmacist pharmacists often add our own analysis and context on top of that licensed data — such as this Bottom Line summary and the notes on individual interaction pages — and any such commentary is noted as ours.

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 reason. St. John's wort is another major entry because it speeds phenytoin's breakdown and can quietly erode seizure control.

Most of the 187 moderate entries work through the same liver enzymes that process phenytoin, nudging its level up or down, and 38 ingredients carry liver toxicity risks of their own, with Siberian cocklebur rated major. Even folic acid at 1 mg or more daily can lower phenytoin levels, and activated charcoal can keep a dose from absorbing at all. Nine of the 224 entries rate major, and those nine are where to focus first.

— , Clinical Pharmacist · July 18, 2026

Major 9 Moderate 187 Minor 28 No known interaction 1,228

This box checks one ingredient at a time (like turmeric or magnesium). Taking a supplement product with a whole label of ingredients? Search the product instead — we check every ingredient on it ↓

Most Viewed Ingredient Interactions

Phenytoin: Top Interactions at a Glance

The Phenytoin supplement & herbal interactions people checked most in the last 24 hours, colored by severity. Tap any ingredient to open the full report for that pair.

Showing the 12 highest-ranked of 224 interacting ingredients — plus 1,228 more checked with no known interaction. See the complete ranked list.

Start here

The Most-Checked Phenytoin Combinations Today

The Phenytoin + supplement pages people viewed most in the last 24 hours (resets at midnight). Open any card for the full report.

Moderate Likelihood Possible Eleuthero + Phenytoini

Theoretically, eleuthero might increase levels of drugs metabolized by CYP2C9.

Read the full interaction Major Likelihood Probable Kava + Phenytoini

Combining kava with CNS depressants can have additive sedative effects.

Read the full interaction Moderate Likelihood Possible Camphor + Phenytoini

Theoretically, concomitant use of camphor with other hepatotoxic drugs might increase the risk of liver damage.

Read the full interaction Moderate Likelihood Possible Neem + Phenytoini

Theoretically, neem leaf extract might increase the levels and clinical effects of CYP2C9 substrates.

Read the full interaction Moderate Likelihood Possible Dusty Miller + Phenytoini

Theoretically, CYP3A4 inducers might increase the risk of adverse effects from the pyrrolizidine alkaloid (PA) constituents in dusty miller.

Read the full interaction Minor Likelihood Possible Hibiscus Sabdariffa + Phenytoini

Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP2C19 substrates.

Read the full interaction
The complete list

Every Supplement Checked Against Phenytoin

All 1,452 ingredients in our database, ranked by severity — 224 with a Phenytoin interaction on file and 1,228 with none found. Filter by severity or search any ingredient; hover the for what each ingredient is.

Looking for an interaction with a specific supplement product? Search products instead ↓

Straight answers

Can You Take It With Phenytoin?

One-line answers, one card per combination — scroll through today’s 20 and tap any card for the full report. A different set rotates in daily until every combination has had its turn.

Can you take Eleuthero with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, eleuthero might increase levels of drugs metabolized by CYP2C9.

Full Eleuthero + Phenytoin answer

Can you take Kava with Phenytoin?

Major Use real caution — this is a major-rated interaction, generally best avoided or used only under close supervision. Combining kava with CNS depressants can have additive sedative effects.

Full Kava + Phenytoin answer

Can you take Camphor with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, concomitant use of camphor with other hepatotoxic drugs might increase the risk of liver damage.

Full Camphor + Phenytoin answer

Can you take Neem with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, neem leaf extract might increase the levels and clinical effects of CYP2C9 substrates.

Full Neem + Phenytoin answer

Can you take Dusty Miller with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, CYP3A4 inducers might increase the risk of adverse effects from the pyrrolizidine alkaloid (PA) constituents in dusty miller.

Full Dusty Miller + Phenytoin answer

Can you take 5-htp with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, concomitant use of 5-HTP with medications that cause sedation might have additive effects.

Full 5-htp + Phenytoin answer

Can you take Adrafinil with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, adrafinil might increase the levels and clinical effects of CYP2C19 substrates.

Full Adrafinil + Phenytoin answer

Can you take Adrue with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Animal research suggests that taking adrue in combination with sodium thiopental or diazepam increases total sleep time up to four-fold comp...

Full Adrue + Phenytoin answer

Can you take African Wild Potato with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. In vitro research shows that African wild potato extract inhibits cytochrome P450 2C9 (CYP2C9).

Full African Wild Potato + Phenytoin answer

Can you take Albizia Julibrissin with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Animal research suggests that certain constituents from Albizia julibrissin flowers can potentiate pentobarbital-induced sleeping time in mi...

Full Albizia Julibrissin + Phenytoin answer

Can you take Alkanna with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Hepatotoxic pyrrolizidine alkaloids (PAs) are substrates of cytochrome P450 3A4 (CYP3A4).

Full Alkanna + Phenytoin answer

Can you take Alpine Ragwort with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, CYP3A4 inducers might increase the risk of adverse effects from the pyrrolizidine alkaloid (PA) constituents in alpine ragwor...

Full Alpine Ragwort + Phenytoin answer

Can you take Artichoke with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, artichoke might increase serum levels of drugs metabolized by CYP2C19.

Full Artichoke + Phenytoin answer

Can you take Ashwagandha with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking ashwagandha might increase the sedative effects of CNS depressants.

Full Ashwagandha + Phenytoin answer

Can you take Bacopa with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, bacopa might increase the levels and adverse effects of CYP2C19 substrates.

Full Bacopa + Phenytoin answer

Can you take Baikal Skullcap with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, Baikal skullcap might increase levels of drugs metabolized by CYP2C19 enzymes.

Full Baikal Skullcap + Phenytoin answer

Can you take Bay Leaf with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking bay leaf in large amounts may enhance the therapeutic and adverse effects of sedatives.

Full Bay Leaf + Phenytoin answer

Can you take Berberine with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, berberine might increase the sedative effects of CNS depressants.

Full Berberine + Phenytoin answer

Can you take Biofeedback with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. There is some concern that electroencephalogram (EEG) biofeedback might lower the seizure threshold in some patients.

Full Biofeedback + Phenytoin answer

Can you take Bitter Almond with Phenytoin?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, bitter almond oil may have additive effects with other CNS depressants.

Full Bitter Almond + Phenytoin answer
Read the list like a pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

  • Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
  • Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
  • Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
  • No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

  • Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
  • Probable. Interaction 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.
  • Possible. 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
  • Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

  • Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
  • Each entry links to a full report with the clinical detail, likelihood, evidence level, and citations for that exact combination.
  • Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

How Does Our Interaction Checker Work?

Behind every verdict on this page is a category system. Our source database doesn’t document supplement interactions drug-by-drug — it documents them against groups of medications that behave the same way (for example, “drugs processed by the CYP3A4 liver enzyme” or “blood-thinning medications”).

So the check works in three steps: (1) Phenytoin is classified into the pharmacology categories it belongs to, (2) every supplement interaction documented against any of those categories is inherited by Phenytoin, and (3) each ingredient keeps its own severity, likelihood, and evidence grades from the underlying record. That’s why one supplement can carry several records for one drug — it may interact through more than one category.

Phenytoin sits in 14 interaction categories. Open any one to see what the group means:

Cns Depressants 78 ingredients

Central-nervous-system depressants. Sedating supplements can intensify drowsiness and slowed reactions when combined.

78 of the supplement ingredients on this page reach Phenytoin through this category.

Cytochrome P450 2C9 (Cyp2C9) Substrates 64 ingredients

A drug-metabolism group: these medications are processed by the named liver enzyme (a cytochrome P450). Supplements that speed this enzyme up or slow it down can lower or raise the medication's levels in your body.

64 of the supplement ingredients on this page reach Phenytoin through this category.

Hepatotoxic Drugs 38 ingredients

Medications with known liver considerations. Supplements that can stress the liver add to the load.

38 of the supplement ingredients on this page reach Phenytoin through this category.

Cytochrome P450 2C19 (Cyp2C19) Substrates 33 ingredients

A drug-metabolism group: these medications are processed by the named liver enzyme (a cytochrome P450). Supplements that speed this enzyme up or slow it down can lower or raise the medication's levels in your body.

33 of the supplement ingredients on this page reach Phenytoin through this category.

Phenytoin (Dilantin) 23 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

23 of the supplement ingredients on this page reach Phenytoin through this category.

Cytochrome P450 3A4 (Cyp3A4) Inducers 19 ingredients

A drug-metabolism group: these medications are processed by the named liver enzyme (a cytochrome P450). Supplements that speed this enzyme up or slow it down can lower or raise the medication's levels in your body.

19 of the supplement ingredients on this page reach Phenytoin through this category.

Oral Drugs 17 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

17 of the supplement ingredients on this page reach Phenytoin through this category.

Anticonvulsants 15 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

15 of the supplement ingredients on this page reach Phenytoin through this category.

Cytochrome P450 2C8 (Cyp2C8) Substrates 11 ingredients

A drug-metabolism group: these medications are processed by the named liver enzyme (a cytochrome P450). Supplements that speed this enzyme up or slow it down can lower or raise the medication's levels in your body.

11 of the supplement ingredients on this page reach Phenytoin through this category.

Seizure Threshold Lowering Drugs 6 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

6 of the supplement ingredients on this page reach Phenytoin through this category.

Cytochrome P450 2C9 (Cyp2C9) Inducers 3 ingredients

A drug-metabolism group: these medications are processed by the named liver enzyme (a cytochrome P450). Supplements that speed this enzyme up or slow it down can lower or raise the medication's levels in your body.

3 of the supplement ingredients on this page reach Phenytoin through this category.

Cytochrome P450 2C19 (Cyp2C19) Inducers 2 ingredients

A drug-metabolism group: these medications are processed by the named liver enzyme (a cytochrome P450). Supplements that speed this enzyme up or slow it down can lower or raise the medication's levels in your body.

2 of the supplement ingredients on this page reach Phenytoin through this category.

Cytochrome P450 1A2 (Cyp1A2) Inducers 1 ingredient

A drug-metabolism group: these medications are processed by the named liver enzyme (a cytochrome P450). Supplements that speed this enzyme up or slow it down can lower or raise the medication's levels in your body.

1 of the supplement ingredient on this page reaches Phenytoin through this category.

Phenytoin (Dilantin) 1 ingredient

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

1 of the supplement ingredient on this page reaches Phenytoin through this category.

About Phenytoin

Phenytoin is an anticonvulsant medication used to control seizures and prevent seizures during or after brain surgery.

Generic name: Phenytoin  ·  Brand names: Dilantin Kapseals, Dilantin, Di-Phen, Dilantin Infatabs, Phenytek, Dilantin injection.

See the full Phenytoin drug information

Related: does Phenytoin deplete any nutrients?

Phenytoin has 78 reported nutrient associations in the research literature — see the Phenytoin nutrient depletion report.

Check a real product

Take a Supplement Product? Check the Whole Bottle Against Phenytoin

Most supplements are combination products — and the interaction may come from an ingredient you didn’t buy it for. Search any product below (or scan its label) and we’ll check every ingredient on it against Phenytoin.

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Type a product name, brand, or UPC — smart search across our full catalog.

Grounded search over our product catalog — every verdict comes from our interaction database, never AI guesswork. How we use AI

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Photograph any Supplement Facts panel — we read the ingredients and check each one against your medications. Free, in seconds.

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Pharmacist Counseling Corner

Phenytoin & Supplements: Common Questions

What supplements interact with Phenytoin?
More than you might expect — 224 in total, though they are far from equal: 9 are rated major, 187 moderate, and 28 minor. The ranked list on this page puts the ones that genuinely matter first, and every entry opens a full report on that exact pair. The highest-ranked right now: Beer, Siberian Cocklebur, St. John's Wort.
Which Phenytoin supplement interactions are the most serious?
The 9 major-rated combinations — led by Beer, Siberian Cocklebur, St. John's Wort, Wine and 1,4-butanediol — deserve real caution: these are the ones generally best avoided, or used only with your prescriber watching. If you take any of them today, don't panic and don't stop anything abruptly — call your pharmacist first. Jump to the ranked list.
Can I take vitamins or supplements while on Phenytoin?
Usually yes — most people on Phenytoin can take most supplements. The catch is the exceptions, and they aren't always the exotic ones (St. John's Wort trips up more prescriptions than almost anything sold next to it). Look up each ingredient you actually take in the list above, and treat "no known interaction" as a green-ish light, not a guarantee. Try the label scanner or the interaction checker.
Do brands like Dilantin Kapseals have the same supplement interactions as Phenytoin?
Yes — Dilantin Kapseals, Dilantin, Di-Phen, Dilantin Infatabs, Phenytek and other brands all contain Phenytoin, so everything on this page applies to them equally. Interactions belong to the active drug, never to the brand on the box; the same is true of generics.
Where do these interaction ratings come from?
Every rating comes from the Natural Medicines database — the same evidence-graded reference pharmacists and hospitals use — and each interaction carries three separate grades: severity (how bad it can be), likelihood (how well it's documented in studies and case reports), and an evidence level. Our pharmacists review the content; we never let an AI decide an interaction. See how to read the ratings and our editorial policy.
Does Phenytoin deplete any vitamins or nutrients?
It might — Phenytoin has 78 reported nutrient-depletion associations in the research literature, which is a different question from interactions: instead of a supplement changing the drug, the drug may lower a nutrient over time. See the Phenytoin nutrient depletion report for the specifics and what to discuss with your pharmacist.
What about Phenytoin and my other medications?
This page covers Phenytoin against supplements and herbal ingredients. Checking Phenytoin against your other prescription or OTC medications is a different tool — our drug interaction checker covers that side. Head to the drug–drug interaction checker, or read the full Phenytoin drug information.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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Sourcing

Where This Data Comes From — and Why You Can Trust It

🧪 Licensed clinical database

Every interaction verdict on this page comes from Natural Medicines Pro (TRC Healthcare / Therapeutic Research) — the same evidence-graded reference used by pharmacists and hospitals. We license this data directly; we do not scrape it, and no AI invents an interaction.

🧑‍⚕️ Pharmacist review

This page is curated and coded by , Clinical Pharmacist, with additional analysis by the HelloPharmacist Pharmacist Team. Editorial commentary is ours; the licensed interaction records are shown as sourced.

🔄 Kept current

Our interaction database refreshes on a weekly cycle, and this page re-checks the live database every time it’s rebuilt — what you see reflects the database as of September 22, 2026.

🔍 Full transparency

How every dataset on this site is sourced, licensed, and updated is documented publicly: our data sources · editorial policy · how we use AI.

Educational information, not medical advice. An interaction being on file does not mean it will happen to you — and absence of one is not proof of safety. Never start or stop a medication or supplement without talking to your pharmacist or doctor.