Drug & supplement interaction

Milk Thistle + Perampanel

Perampanel brand name: Fycompa.

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

Perampanel falls into 2 drug categories that Milk Thistle can interact with; the most serious is rated minor. It is unclear if milk thistle inhibits CYP2C9; research is conflicting.

Read the full interaction report
SeverityMinor
LikelihoodUnlikely
Interactions2
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Milk Thistle and Perampanel

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

Why Are There 2 Interactions?

Milk Thistle interacts with whole categories of medication. Perampanel falls into 2 of those categories, so it can interact with Milk Thistle in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Minor).

Minor

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

1 of 2

Why this applies to Perampanel

Perampanel falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES — the group Milk Thistle interacts with.

It is unclear if milk thistle inhibits CYP2C9; research is conflicting.
In vitro research suggests that milk thistle might inhibit CYP2C9. Additionally, 3 case reports from the World Health Organization (WHO) adverse drug reaction database describe increased toxicity in patients taking milk thistle and cancer medications that are CYP2C9 substrates, including imatinib and capecitabine. However, contradictory clinical research shows that milk thistle extract does not inhibit CYP2C9 or significantly affect levels of the CYP2C9 substrate tolbutamide. Differences in results could be due to differences in dosages or formulations utilized.
Severity Minor Likelihood Unlikely Evidence B

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the gist for Perampanel (Fycompa): your body partly clears it using a liver enzyme called CYP2C9. Milk thistle has been looked at as a possible blocker of that same enzyme. If it did slow CYP2C9 down, perampanel could build up a bit, which might mean more of its usual side effects like dizziness, drowsiness, trouble with balance, or mood and irritability changes.

The good news is the evidence here is shaky and conflicting. Lab studies hint at a small effect, but better human research suggests milk thistle doesn't meaningfully block CYP2C9. So a real-world problem is unlikely. Still, perampanel is a seizure medicine where steadiness matters, so check with your pharmacist or doctor before adding milk thistle.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Beckmann-Knopp S, Rietbrock S, Weyhenmeyer R, et al. Inhibitory effects of silibinin on cytochrome P-450 enzymes in human liver microsomes. Pharmacol Toxicol 2000;86:250-6. PubMed
  2. Gurley BJ, Gardner SF, Hubbard MA, et al. In vivo assessment of botanical supplementation on human cytochrome P450 phenotypes: Citrus aurantium, Echinacea purpurea, milk thistle, and saw palmetto. Clin Pharmacol Ther 2004;76:428-40. .
  3. Sridar C, Goosen TC, Kent UM, et al. Silybin inactivates cytochromes P450 3A4 and 2C9 and inhibits major hepatic glucuronosyltransferases. Drug Metab Dispos 2004;32:587-94. PubMed
  4. Doehmer J, Weiss G, McGregor GP, Appel K. Assessment of a dry extract from milk thistle (Silybum marianum) for interference with human liver cytochrome-P450 activities. Toxicol In Vitro 2011;25:21-7. PubMed
  5. Kawaguchi-Suzuki M, Frye RF, Zhu HJ, et al. The effects of milk thistle (Silybum marianum) on human cytochrome P450 activity. Drug Metab Dispos. 2014;42(10):1611-6. PubMed
  6. Pochet S, Lechon AS, Lescrainier C, et al. Herb-anticancer drug interactions in real life based on VigiBase, the WHO global database. Sci Rep 2022;12(1):14178. PubMed
Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 2

Perampanel also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

It is unclear if milk thistle inhibits CYP3A4; research is conflicting.
While laboratory research shows conflicting results, pharmacokinetic research shows that taking milk thistle extract 420-1350 mg daily does not significantly affect the metabolism of the CYP3A4 substrates irinotecan, midazolam, or indinavir. However, 8 case reports from the World Health Organization (WHO) adverse drug reaction database describe increased toxicity in patients taking milk thistle and cancer medications that are CYP3A4 substrates, including gefitinib, sorafenib, doxorubicin, and vincristine.
Severity Minor Likelihood Unlikely Evidence D

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the short version: your body clears Perampanel mainly through a liver enzyme called CYP3A4. In theory, if milk thistle slowed that enzyme down, more Perampanel could linger in your system, which might mean more of its usual effects like drowsiness, dizziness, trouble with balance, or irritability. But the evidence for this is thin, mostly lab and animal data, and human studies actually show milk thistle didn't meaningfully change how the body handled other CYP3A4 drugs.

Perampanel is not a prodrug, so it doesn't need this enzyme to become active. Overall I'd call this a low-concern combination for most people. Still, since Perampanel can already make you sleepy, mention milk thistle to your pharmacist or doctor so they can keep an eye on how you feel.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Venkataramanan R, Ramachandran V, Komoroski BJ, et al. Milk thistle, a herbal supplement, decreases the activity of CYP3A4 and uridine diphosphoglucuronosyl transferase in human hepatocyte cultures. Drug Metab Dispos 2000;28:1270-3. DOI
  2. Piscitelli SC, Formentini E, Burstein AH, et al. Effect of milk thistle on the pharmacokinetics of indinavir in healthy volunteers. Pharmacotherapy 2002;22:551-6. PubMed
  3. Sridar C, Goosen TC, Kent UM, et al. Silybin inactivates cytochromes P450 3A4 and 2C9 and inhibits major hepatic glucuronosyltransferases. Drug Metab Dispos 2004;32:587-94. PubMed
  4. van Erp NP, Baker SD, Zhao M, et al. Effect of milk thistle (Silybum marianum) on the pharmacokinetics of irinotecan. Clin Cancer Res 2005;11:7800-6.
  5. Budzinski JW, Trudeau VL, Drouin CE, et al. Modulation of human cytochrome P450 3A4 (CYP3A4) and P-glycoprotein (P-gp) in Caco-2 cell monolayers by selected commercial-source milk thistle and goldenseal products. Can J Physiol Pharmacol 2007;85:966-78.
  6. Doehmer J, Weiss G, McGregor GP, Appel K. Assessment of a dry extract from milk thistle (Silybum marianum) for interference with human liver cytochrome-P450 activities. Toxicol In Vitro 2011;25:21-7. PubMed
  7. Jalloh MA, Gregory PJ, Hein D, et al. Dietary supplement interactions with antiretrovirals: a systematic review. Int J STD AIDS. 2017 Jan;28(1):4-15. PubMed
  8. Kawaguchi-Suzuki M, Frye RF, Zhu HJ, et al. The effects of milk thistle (Silybum marianum) on human cytochrome P450 activity. Drug Metab Dispos. 2014;42(10):1611-6. PubMed
  9. Pochet S, Lechon AS, Lescrainier C, et al. Herb-anticancer drug interactions in real life based on VigiBase, the WHO global database. Sci Rep 2022;12(1):14178. 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

Milk Thistle Also Interacts With Other Medications

Milk Thistle has 254 moderate, 699 minor known drug interactions in our database — the Perampanel one above is among them. If you take anything else, check it against the full list below.

Moderate 254 Minor 699 No known interaction 1,877 (incl. Perampanel)
Taking anything else?

Check Another of Your Medications Against Milk Thistle

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

From our Q&A

Questions About Milk Thistle or Perampanel

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Milk Thistle or Perampanel, 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 Perampanel

This page covers Milk Thistle only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Perampanel page lists 230 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 Grapefruit (major).

By severity: 9 major · 175 moderate · 46 minor.

From our pharmacist’s overview on the Perampanel page

“Perampanel (Fycompa) is a seizure medicine that already causes drowsiness and dizziness on its own, which is why I treat this list of 230 interacting supplements with real care. Most entries do one of two things: they add to its sedating effect, as alcohol and kava do, or they change how the liver handles it.”

Reviewed by 2 · Jul 18, 2026

Open the Perampanel interaction page

One more smart check

Taking Milk Thistle as Part of a Dietary Supplement Product? Check It for Interactions

We hold 4,560 real supplement products containing Milk Thistle, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Milk Thistle. Your product may carry other ingredients that interact with Perampanel too, on top of Milk Thistle — 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 Milk Thistle and Perampanel 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 Milk Thistle
Top 5%

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

29 days ago today
Medication Perampanel
Steady interest

#1,988 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 Milk Thistle

What is Milk Thistle?

Milk Thistle
  • Liver health and protection
  • Hepatitis
  • Cirrhosis
  • Gallbladder problems
  • High cholesterol
  • Type 2 diabetes support

Milk thistle is a popular herbal supplement most often used for liver health, and its main active component is a group of compounds called silymarin. While it is generally well tolerated, the scientific evidence that it meaningfully improves liver disease or other conditions is mixed and far from conclusive. Talk with your pharmacist or doctor before using it, especially if you have a liver condition or take other medicines.

Read the full Milk Thistle monograph & all interactions
Medication

About Perampanel

What Is Perampanel Used For?

Brand name: Fycompa

Perampanel — available as Fycompa and in generic forms — is used to treat partial-onset seizures (seizures that start in one area of the brain) in patients with epilepsy aged 4 years and older. Both the tablet and oral suspension forms carry this indication.

Perampanel tablets and oral suspension are also approved as add-on (adjunctive) therapy for primary generalized tonic-clonic seizures (grand mal seizures involving the whole brain at once) in patients with epilepsy aged 12 years and older. Fycompa oral suspension and tablet share both indications.

See full Perampanel drug information
Keep checking

Other Drugs & Milk Thistle

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

0Major
254Moderate
699Minor
1,876No known interaction
254 Moderate 699 Minor 1,876 No interaction
Moderate

254 interactions

Showing 60 of 254 moderate interactions — see all 254 on the Milk Thistle page.

Minor

699 interactions

Showing 60 of 699 minor interactions — see all 699 on the Milk Thistle page.

No interaction 1,876 drugs checked — show the list

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

Showing the 60 most looked-up of 1,876 medications checked with no known interaction — see the full Milk Thistle list.

See the full Milk Thistle interactions page
See every supplement checked against Perampanel, 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
Milk Thistle monograph › Uses, safety, and every drug interaction in one place Perampanel supplement interactions › Every supplement checked against Perampanel, ranked by severity Perampanel 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 Milk Thistle and Perampanel Together: Common Questions

Can you take Milk Thistle with Perampanel?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 2 interactions listed for Milk Thistle and Perampanel?
Perampanel belongs to more than one drug category, and Milk Thistle 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 Milk Thistle and Perampanel interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Perampanel and Milk Thistle?

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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.