Drug & supplement interaction

Purple Nut Sedge + Thioridazine

Thioridazine brand name: Mellaril.

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

Purple Nut Sedge has a moderate interaction with Thioridazine. In vitro, purple nut sedge dose-dependently inhibits acetylcholinesterase (AChE).

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

Purple Nut Sedge and Thioridazine

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

Moderate

ANTICHOLINERGIC DRUGS

Why this applies to Thioridazine

Thioridazine falls under ANTICHOLINERGIC DRUGS — the group Purple Nut Sedge interacts with.

In vitro, purple nut sedge dose-dependently inhibits acetylcholinesterase (AChE). Theoretically, concurrent use of anticholinergic drugs and purple nut sedge might decrease the effectiveness of purple nut sedge or the anticholinergic agent.
Some anticholinergic drugs include atropine, benztropine (Cogentin), biperiden (Akineton), procyclidine (Kemadrin), and trihexyphenidyl (Artane).
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 gist for thioridazine (Mellaril): it has anticholinergic activity, meaning part of how it acts is by blocking the chemical messenger acetylcholine. Purple nut sedge does the opposite in lab studies, where it blocks the enzyme that breaks down acetylcholine, so more of that messenger sticks around. In theory, the two could partly cancel each other out, meaning the supplement may not work as hoped and the drug's effects could be slightly blunted.

I want to be honest about the strength here: this is based only on test-tube and animal data, not real people, so it's very theoretical and rated as possible at most. That said, thioridazine is a serious medication with real risks (drowsiness, dry mouth, dizziness, and heart rhythm concerns), so don't add or stop anything on your own. Run it by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sharma R, Gupta R. Cyperus rotundus extract inhibits acetylcholinesterase activity from animal and plants as well as inhibits germination and seedling growth in wheat and tomato. Life Sci. 2007;80(24-25):2389-2392. 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

Purple Nut Sedge Also Interacts With Other Medications

Purple Nut Sedge has 423 moderate known drug interactions in our database — the Thioridazine one above is one of them. If you take anything else, check it against the full list below.

Moderate 423 No known interaction 2,407 (incl. Thioridazine)
Taking anything else?

Check Another of Your Medications Against Purple Nut Sedge

Covers the 2,830 medications we’ve checked against Purple Nut Sedge. Pick one to open its full report.

From our Q&A

Questions About Purple Nut Sedge or Thioridazine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Purple Nut Sedge or Thioridazine, 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 Thioridazine

This page covers Purple Nut Sedge only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Thioridazine page lists 168 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 11 major · 125 moderate · 32 minor.

From our pharmacist’s overview on the Thioridazine page

“Thioridazine (Mellaril) is an older antipsychotic already known for disturbing the heart's rhythm, and the supplements that worry me most here do the same thing, stretching the QT interval further. Grapefruit in large amounts sits in that group, alongside ephedra and several other major-rated entries.”

Reviewed by 2 · Jul 18, 2026

Open the Thioridazine interaction page

How much people look this up

Where Purple Nut Sedge and Thioridazine 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 Purple Nut Sedge
Top half

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

29 days ago today
Medication Thioridazine
Top half

#1,200 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 Purple Nut Sedge

What is Purple Nut Sedge?

  • Digestive upset and bloating
  • Menstrual cramps and irregular periods
  • Fever and inflammation
  • Skin and weight-related concerns
  • Antimicrobial uses

Purple nut sedge (Cyperus rotundus) is a common weed whose tubers have a long history in Ayurvedic, Chinese, and other traditional medicine systems, mostly for digestive and menstrual complaints. Modern human evidence is very limited, so its benefits remain unproven. If you want to try it, talk with a pharmacist or doctor first, and avoid it during pregnancy and breastfeeding.

Read the full Purple Nut Sedge monograph & all interactions
Medication

About Thioridazine

What Is Thioridazine Used For?

Brand name: Mellaril

Thioridazine Hydrochloride tablets are used for the management of schizophrenia — but only in patients who have already tried at least two other antipsychotic medications without adequate results, either because those drugs didn't work well enough or caused intolerable side effects.

Because thioridazine carries serious heart-rhythm risks, it is considered a last-resort option for schizophrenia, not a first-line treatment. It is not approved for dementia-related psychosis or any other psychiatric condition.

See full Thioridazine drug information
Keep checking

Other Drugs & Purple Nut Sedge

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

0Major
423Moderate
0Minor
2,406No known interaction
423 Moderate 2,406 No interaction
Moderate

423 interactions

Showing 60 of 423 moderate interactions — see all 423 on the Purple Nut Sedge page.

No interaction 2,406 drugs checked — show the list

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

Showing the 60 most looked-up of 2,406 medications checked with no known interaction — see the full Purple Nut Sedge list.

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

Can you take Purple Nut Sedge with Thioridazine?
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 Purple Nut Sedge and Thioridazine 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 Thioridazine and Purple Nut Sedge?

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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.