Drug & supplement interaction

Purple Nut Sedge + Chlorpheniramine, Methscopolamine, Phenylephrine

Chlorpheniramine, Methscopolamine, Phenylephrine brand names: DA II, Extendryl JR, Dallergy, Extendryl SR, Extendryl Chews, and others.

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

Purple Nut Sedge has a moderate interaction with Chlorpheniramine, Methscopolamine, Phenylephrine. 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 Chlorpheniramine, Methscopolamine, Phenylephrine

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

Moderate

ANTICHOLINERGIC DRUGS

Why this applies to Chlorpheniramine, Methscopolamine, Phenylephrine

Chlorpheniramine, Methscopolamine, Phenylephrine 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 this combo. Two ingredients in your medicine, the antihistamine chlorpheniramine and especially methscopolamine, work partly by blocking acetylcholine, a nerve-signaling chemical. In lab dishes, purple nut sedge does the opposite: it slows the enzyme that breaks acetylcholine down, leaving more of it around. So in theory, the two could partly cancel each other out, making the supplement or the medicine less effective.

I want to be honest about the strength of this, though. It comes only from test-tube and animal research, not from people, so it may not matter much in real life. If it did, you might just notice your allergy or congestion symptoms not easing as well. There's no clear danger here, but it's still worth a quick word with your pharmacist or doctor before combining them.

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 Chlorpheniramine, Methscopolamine, Phenylephrine 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. Chlorpheniramine, Methscopolamine, Phenylephrine)
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.

Everything else you take

See Every Supplement That Interacts With Chlorpheniramine, Methscopolamine, Phenylephrine

This page covers Purple Nut Sedge only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Chlorpheniramine, Methscopolamine, Phenylephrine page lists 230 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Ephedra (major), Grapefruit (major), Henbane (major) and Lithium (major).

By severity: 10 major · 175 moderate · 45 minor.

From our pharmacist’s overview on the Chlorpheniramine, Methscopolamine, Phenylephrine page

“This allergy and congestion combination, Chlorpheniramine, Methscopolamine, and Phenylephrine (Dallergy, Extendryl), has 230 supplement and herbal ingredients on its interaction list, and 10 of them carry major ratings, so this is a list to check carefully rather than skim. The largest group works through the liver enzyme that breaks t…”

Reviewed by 2 · Jul 18, 2026

Open the Chlorpheniramine, Methscopolamine, Phenylephrine interaction page

How much people look this up

Where Purple Nut Sedge and Chlorpheniramine, Methscopolamine, Phenylephrine 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

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

29 days ago today
Medication Chlorpheniramine, Methscopolamine, Phenylephrine
Top 25%

#456 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
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 Chlorpheniramine, Methscopolamine, Phenylephrine, 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 Chlorpheniramine, Methscopolamine, Phenylephrine supplement interactions › Every supplement checked against Chlorpheniramine, Methscopolamine, Phenylephrine, 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 Purple Nut Sedge and Chlorpheniramine, Methscopolamine, Phenylephrine Together: Common Questions

Can you take Purple Nut Sedge with Chlorpheniramine, Methscopolamine, Phenylephrine?
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 Chlorpheniramine, Methscopolamine, Phenylephrine 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 Chlorpheniramine, Methscopolamine, Phenylephrine 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.