Drug & supplement interaction

Hemp Agrimony + Mephenytoin

Mephenytoin brand name: Mesantoin.

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

Mephenytoin falls into 2 drug categories that Hemp Agrimony can interact with; the most serious is rated moderate. Hemp agrimony contains hepatotoxic pyrrolizidine alkaloids (PA).

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Hemp Agrimony and Mephenytoin

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

Why Are There 2 Interactions?

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

Moderate

HEPATOTOXIC DRUGS

1 of 2

Why this applies to Mephenytoin

Mephenytoin falls under HEPATOTOXIC DRUGS — the group Hemp Agrimony interacts with.

Hemp agrimony contains hepatotoxic pyrrolizidine alkaloids (PA). Theoretically, using hemp agrimony with hepatotoxic drugs might have additive adverse effects on the liver. Some drugs that can adversely affect the liver include acetaminophen (Tylenol and others), amiodarone (Cordarone), carbamazepine (Tegretol), isoniazid (INH), methotrexate (Rheumatrex), methyldopa (Aldomet), fluconazole (Diflucan), itraconazole (Sporanox), erythromycin (Erythrocin, Ilosone, others), phenytoin (Dilantin), lovastatin (Mevacor), pravastatin (Pravachol), simvastatin (Zocor), and many 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 concern with pairing hemp agrimony and mephenytoin (Mesantoin). This herb can contain pyrrolizidine alkaloids, natural compounds that may be tough on the liver. Mephenytoin, an older seizure medicine, is itself processed by the liver and can occasionally stress it too. Put the two together and you may be adding liver strain on top of liver strain.

I'll be honest: this interaction is theoretical, based on how each one behaves rather than proven cases, so I don't want to alarm you. Still, since hemp agrimony's liver risk is real enough that many experts advise against taking it internally at all, I'd skip it here. If you notice yellowing skin, dark urine, belly pain, or unusual tiredness, call your doctor. Please check with your pharmacist before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Chojkier M. Hepatic sinusoidal-obstruction syndrome: toxicity of pyrrolizidine alkaloids. J Hepatol 2003;39:437-46. PubMed
  2. Wang YP, Yan J, Fu PP, Chou MW. Human liver microsomal reduction of pyrrolizidine alkaloid N-oxides to form the corresponding carcinogenic parent alkaloid. Toxicol Lett 2005;155:411-20. PubMed
Moderate

CYTOCHROME P450 3A4 (CYP3A4) INDUCERS

2 of 2

Mephenytoin also falls under CYTOCHROME P450 3A4 (CYP3A4) INDUCERS.

Hemp agrimony contains hepatotoxic pyrrolizidine alkaloids (PA) which are substrates of cytochrome P450 3A4 (CYP3A4). Theoretically, drugs that induce CYP3A4 might increase the conversion of PAs to toxic metabolites. Some drugs that induce CYP3A4 include carbamazepine (Tegretol), phenobarbital, phenytoin (Dilantin), rifampin, rifabutin (Mycobutin), 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 key thing to understand about this pairing: it's not that hemp agrimony changes how your Mephenytoin works. It's the other way around. Mephenytoin can speed up a liver enzyme called CYP3A4, the same enzyme that turns the natural compounds in hemp agrimony (called pyrrolizidine alkaloids) into byproducts that may be hard on the liver. So in theory, taking the two together could lead to more of those potentially harmful liver byproducts forming.

I'll be honest with you: this is based on lab and animal data, not real human studies, so the risk is theoretical. But hemp agrimony already isn't recommended for internal use because of those liver-stressing compounds, and combining it with a strong enzyme-revving drug like Mephenytoin only adds caution. Please check with your pharmacist or doctor before using any hemp agrimony product.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Chojkier M. Hepatic sinusoidal-obstruction syndrome: toxicity of pyrrolizidine alkaloids. J Hepatol 2003;39:437-46. PubMed
  2. Wang YP, Yan J, Fu PP, Chou MW. Human liver microsomal reduction of pyrrolizidine alkaloid N-oxides to form the corresponding carcinogenic parent alkaloid. Toxicol Lett 2005;155:411-20. 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

Hemp Agrimony Also Interacts With Other Medications

Hemp Agrimony has 437 moderate known drug interactions in our database — the Mephenytoin one above is among them. If you take anything else, check it against the full list below.

Moderate 437 No known interaction 2,393 (incl. Mephenytoin)
Taking anything else?

Check Another of Your Medications Against Hemp Agrimony

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

Everything else you take

See Every Supplement That Interacts With Mephenytoin

This page covers Hemp Agrimony only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Mephenytoin page lists 215 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 · 178 moderate · 28 minor.

From our pharmacist’s overview on the Mephenytoin page

“Anyone taking mephenytoin (Mesantoin) for seizures should read this page with genuine care rather than as background noise. The biggest cluster of interactions piles sedation on top of a drug that already slows the nervous system, and alcohol, whether beer or wine, sits at the serious end of that group.”

Reviewed by 2 · Jul 18, 2026

Open the Mephenytoin interaction page

One more smart check

Taking Hemp Agrimony as Part of a Dietary Supplement Product? Check It for Interactions

We hold 3 real supplement products containing Hemp Agrimony, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Hemp Agrimony. Your product may carry other ingredients that interact with Mephenytoin too, on top of Hemp Agrimony — 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 Hemp Agrimony and Mephenytoin 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 Hemp Agrimony
Top half

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

29 days ago today
Medication Mephenytoin
Steady interest

#2,099 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 Hemp Agrimony

What is Hemp Agrimony?

Hemp Agrimony
  • Digestive complaints
  • Cold and flu symptoms
  • Respiratory conditions
  • Mild fever
  • Traditional 'tonic' or detox use

Hemp agrimony is a traditional European herb that has been used for digestion, colds, and as a general tonic, but there is very little reliable human research to support these uses. More importantly, the plant can contain pyrrolizidine alkaloids that may harm the liver, so most experts do not recommend taking it internally. Talk with your pharmacist or doctor before using any product that contains hemp agrimony.

Read the full Hemp Agrimony monograph & all interactions
Keep checking

Other Drugs & Hemp Agrimony

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

0Major
437Moderate
0Minor
2,392No known interaction
437 Moderate 2,392 No interaction
Moderate

437 interactions

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

No interaction 2,392 drugs checked — show the list

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

Showing the 60 most looked-up of 2,392 medications checked with no known interaction — see the full Hemp Agrimony list.

See the full Hemp Agrimony interactions page
See every supplement checked against Mephenytoin, 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
Hemp Agrimony monograph › Uses, safety, and every drug interaction in one place Mephenytoin supplement interactions › Every supplement checked against Mephenytoin, 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 Hemp Agrimony and Mephenytoin Together: Common Questions

Can you take Hemp Agrimony with Mephenytoin?
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.
Why are there 2 interactions listed for Hemp Agrimony and Mephenytoin?
Mephenytoin belongs to more than one drug category, and Hemp Agrimony 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 Hemp Agrimony and Mephenytoin 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

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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.