Drug & supplement interaction

Indian Long Pepper + 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

Indian Long Pepper has a moderate interaction with Phenytoin. Theoretically, Indian long pepper might increase blood levels of phenytoin.

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

Indian Long Pepper and Phenytoin

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

Moderate

PHENYTOIN (Dilantin)

Theoretically, Indian long pepper might increase blood levels of phenytoin.
A small pharmacokinetic study shows that piperine, a constituent of Indian long pepper, increases phenytoin serum levels and slows its elimination.
Severity Moderate Likelihood Possible Evidence B

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: phenytoin is a fussy medication with a narrow safety window, meaning the difference between just enough and too much is small. The piperine in Indian long pepper can slow how fast your body clears phenytoin, so the drug may pile up in your blood. A small human study actually showed this happening, so it's more than just a hunch, though the evidence is still limited.

If your phenytoin levels creep up, you might notice things like dizziness, unsteady walking, slurred speech, blurred or jumpy vision, drowsiness, or nausea. Please don't change anything on your own. Just let your pharmacist or doctor know you're using this spice as a supplement, since they may want to check a phenytoin level. Occasional culinary amounts are far less of a worry than concentrated daily supplements.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Bano G, Amla V, Raina RK, et al. The effect of piperine on pharmacokinetics of phenytoin in healthy volunteers. Planta Med 1987;53:568-9. 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

Indian Long Pepper Also Interacts With Other Medications

Indian Long Pepper has 892 moderate, 3 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 892 Minor 3 No known interaction 1,935 (incl. Phenytoin)
Taking anything else?

Check Another of Your Medications Against Indian Long Pepper

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

From our Q&A

Questions About Indian Long Pepper 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 Indian Long Pepper 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 Indian Long Pepper 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

One more smart check

Taking Indian Long Pepper as Part of a Dietary Supplement Product? Check It for Interactions

We hold 597 real supplement products containing Indian Long Pepper, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Indian Long Pepper. Your product may carry other ingredients that interact with Phenytoin too, on top of Indian Long Pepper — 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 Indian Long Pepper 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 Indian Long Pepper
Top 25%

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

29 days ago today
Medication Phenytoin
Steady interest

#1,804 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 Indian Long Pepper

What is Indian Long Pepper?

Indian Long Pepper
  • Digestive upset
  • Respiratory and cough complaints
  • Boosting absorption of other supplements
  • Pain and inflammation
  • General wellness in Ayurveda

Indian long pepper (pippali) is a spice long used in Ayurvedic medicine and is best known for its piperine content, which may increase how well the body absorbs certain other substances. Modern human research on its health benefits is limited, so use it cautiously and let your pharmacist or doctor know if you take it regularly.

Read the full Indian Long Pepper 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 & Indian Long Pepper

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

0Major
892Moderate
3Minor
1,934No known interaction
892 Moderate 3 Minor 1,934 No interaction
Moderate

892 interactions

Showing 60 of 892 moderate interactions — see all 892 on the Indian Long Pepper page.

Minor

3 interactions

No interaction 1,934 drugs checked — show the list

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

Showing the 60 most looked-up of 1,934 medications checked with no known interaction — see the full Indian Long Pepper list.

See the full Indian Long Pepper 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
Indian Long Pepper 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 Indian Long Pepper and Phenytoin Together: Common Questions

Can you take Indian Long Pepper 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 Indian Long Pepper 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 Indian Long Pepper?

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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.