Drug & supplement interaction

Vitex Agnus-castus + Zonisamide

Zonisamide brand names: Zonegran, Zonisade.

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

Vitex Agnus-castus has a moderate interaction with Zonisamide. Theoretically, vitex agnus-castus could interfere with dopamine agonists.

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

Vitex Agnus-castus and Zonisamide

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

Moderate

DOPAMINE AGONISTS

Why this applies to Zonisamide

Zonisamide falls under DOPAMINE AGONISTS — the group Vitex Agnus-castus interacts with.

Theoretically, vitex agnus-castus could interfere with dopamine agonists.
Vitex agnus-castus might potentiate the actions of dopaminergic agonists due to possible dopaminergic effects.
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 honest version for you. This interaction on file was written for dopamine agonists, the Parkinson's-type medicines that mimic dopamine in the brain. The idea is that vitex (chasteberry) may have mild dopamine-like activity of its own and could add to those drugs' effects. The catch is that zonisamide isn't really a dopamine agonist. It's a seizure medicine that calms abnormal electrical activity, so this particular concern doesn't fit it well.

On top of that, the evidence here is theoretical, based only on lab and animal studies, so I wouldn't lose sleep over it. Still, since zonisamide controls seizures, don't add or stop any supplement on your own. Run vitex by your pharmacist or neurologist first so they can check your full picture.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Meier B, Berger D, Hoberg E, et al. Pharmacological activities of Vitex agnus-castus extracts in vitro. Phytomedicine 2000;7:373-81. 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

Vitex Agnus-castus Also Interacts With Other Medications

Vitex Agnus-castus has 120 moderate known drug interactions in our database — the Zonisamide one above is one of them. If you take anything else, check it against the full list below.

Moderate 120 No known interaction 2,710 (incl. Zonisamide)
Taking anything else?

Check Another of Your Medications Against Vitex Agnus-castus

Covers the 2,830 medications we’ve checked against Vitex Agnus-castus. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Zonisamide

This page covers Vitex Agnus-castus only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Zonisamide page lists 206 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 · 157 moderate · 40 minor.

From our pharmacist’s overview on the Zonisamide page

“Zonisamide (Zonegran, Zonisade) keeps seizures under control, which means anything that shifts its blood level or stacks extra sedation on top deserves real respect, and nine of the 206 supplement ingredients on file rate major. Two big themes run through nearly everything here.”

Reviewed by 2 · Jul 18, 2026

Open the Zonisamide interaction page

One more smart check

Taking Vitex Agnus-castus as Part of a Dietary Supplement Product? Check It for Interactions

We hold 45 real supplement products containing Vitex Agnus-castus, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Vitex Agnus-castus. Your product may carry other ingredients that interact with Zonisamide too, on top of Vitex Agnus-castus — 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 Vitex Agnus-castus and Zonisamide 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 Vitex Agnus-castus
Top half

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

29 days ago today
Medication Zonisamide
Top 25%

#635 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 Vitex Agnus-castus

What is Vitex Agnus-castus?

Vitex Agnus-castus
  • Premenstrual syndrome (PMS)
  • Irregular or absent menstrual periods
  • Cyclical breast pain (mastalgia)
  • Menopause symptoms
  • Fertility support

Vitex (chasteberry) is an herbal remedy most often used for PMS and menstrual cycle problems, and the strongest evidence is for easing some PMS symptoms. It is generally well tolerated by many adults, but it can affect hormone-related processes, so anyone who is pregnant, breastfeeding, or has a hormone-sensitive condition should talk with a healthcare professional first.

Read the full Vitex Agnus-castus monograph & all interactions
Medication

About Zonisamide

What Is Zonisamide Used For?

Brand names: Zonegran, Zonisade

Zonisamide is used as add-on therapy — meaning it is combined with other seizure medications, not used alone — to treat partial seizures (seizures that start in one part of the brain) in adults with epilepsy. Zonegran (capsule) and generic zonisamide capsules are approved for adults with epilepsy.

Zonisade (oral suspension) is approved as add-on therapy for partial-onset seizures in adults and in patients 16 years of age and older.

See full Zonisamide drug information
Keep checking

Other Drugs & Vitex Agnus-castus

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

0Major
120Moderate
0Minor
2,709No known interaction
120 Moderate 2,709 No interaction
Moderate

120 interactions

Showing 60 of 120 moderate interactions — see all 120 on the Vitex Agnus-castus page.

No interaction 2,709 drugs checked — show the list

We also checked Vitex Agnus-castus against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,709 medications checked with no known interaction — see the full Vitex Agnus-castus list.

See the full Vitex Agnus-castus interactions page
See every supplement checked against Zonisamide, 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
Vitex Agnus-castus monograph › Uses, safety, and every drug interaction in one place Zonisamide supplement interactions › Every supplement checked against Zonisamide, ranked by severity Zonisamide 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 Vitex Agnus-castus and Zonisamide Together: Common Questions

Can you take Vitex Agnus-castus with Zonisamide?
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 Vitex Agnus-castus and Zonisamide 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 Zonisamide and Vitex Agnus-castus?

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.