Drug & supplement interaction

Corkwood Tree + Chlorpheniramine, Pheylephrine, Pyrilamine

Chlorpheniramine, Pheylephrine, Pyrilamine brand name: Phena-Plus.

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

Corkwood Tree has a moderate interaction with Chlorpheniramine, Pheylephrine, Pyrilamine. Theoretically, corkwood tree might increase the risk of adverse anticholinergic effects when taken with anticholinergic drugs.

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

Corkwood Tree and Chlorpheniramine, Pheylephrine, Pyrilamine

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

Moderate

ANTICHOLINERGIC DRUGS

Why this applies to Chlorpheniramine, Pheylephrine, Pyrilamine

Chlorpheniramine, Pheylephrine, Pyrilamine falls under ANTICHOLINERGIC DRUGS — the group Corkwood Tree interacts with.

Theoretically, corkwood tree might increase the risk of adverse anticholinergic effects when taken with anticholinergic drugs.
Corkwood tree contains the anticholinergic constituents atropine and scopolamine, and ingestion of corkwood tree leaves has been reported to cause effects consistent with anticholinergic toxicity.
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 thing to know about Phena-Plus: the chlorpheniramine and pyrilamine pieces are antihistamines that already carry their own drying, anticholinergic side effects. The Corkwood Tree plant is loaded with similar compounds (atropine and scopolamine), so stacking them is basically piling the same effect on top of itself. That can leave you with a very dry mouth, blurry vision, constipation, trouble urinating, a racing heartbeat, and confusion or drowsiness, especially in older folks.

This is a theoretical concern based on how these chemicals work rather than firm studies, but raw Corkwood Tree leaves are genuinely toxic and aren't meant to be taken as a supplement at all. Please don't combine them, and check with your pharmacist or doctor before using either one.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Pellowe E, Poncia HD. Duboisia ingestion: an unusual cause of anticholinergic poisoning. Emerg Med Australas 2013;25(3):268-70.

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

Corkwood Tree Also Interacts With Other Medications

Corkwood Tree has 194 moderate known drug interactions in our database — the Chlorpheniramine, Pheylephrine, Pyrilamine one above is one of them. If you take anything else, check it against the full list below.

Moderate 194 No known interaction 2,636 (incl. Chlorpheniramine, Pheylephrine, Pyrilamine)
Taking anything else?

Check Another of Your Medications Against Corkwood Tree

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

Everything else you take

See Every Supplement That Interacts With Chlorpheniramine, Pheylephrine, Pyrilamine

This page covers Corkwood Tree only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Chlorpheniramine, Pheylephrine, Pyrilamine page lists 198 supplements it has a documented interaction with, worst first, each one explained.

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

By severity: 6 major · 149 moderate · 43 minor.

From our pharmacist’s overview on the Chlorpheniramine, Pheylephrine, Pyrilamine page

“Reaching for Phena-Plus (chlorpheniramine, phenylephrine, and pyrilamine) usually means a miserable cold or allergy flare, and the same cabinet often holds grapefruit juice or St. John's wort.”

Reviewed by 2 · Jul 18, 2026

Open the Chlorpheniramine, Pheylephrine, Pyrilamine interaction page

How much people look this up

Where Corkwood Tree and Chlorpheniramine, Pheylephrine, Pyrilamine 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 Corkwood Tree
Steady interest

#1,099 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Chlorpheniramine, Pheylephrine, Pyrilamine
Top 25%

#366 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 Corkwood Tree

What is Corkwood Tree?

  • Source of scopolamine and hyoscyamine alkaloids
  • Traditional use as a stimulant or for fatigue
  • Historic use for motion sickness (via its alkaloids)
  • Antispasmodic / smooth muscle effects

Corkwood Tree (Duboisia myoporoides) is an Australian plant best known as a commercial source of powerful tropane alkaloids like scopolamine and hyoscyamine, not as a safe home remedy. The raw plant is highly toxic and should not be used as a dietary supplement; only purified, medically prescribed alkaloids derived from it should be used, and only under a doctor's care.

Read the full Corkwood Tree monograph & all interactions
Keep checking

Other Drugs & Corkwood Tree

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

0Major
194Moderate
0Minor
2,635No known interaction
194 Moderate 2,635 No interaction
Moderate

194 interactions

Showing 60 of 194 moderate interactions — see all 194 on the Corkwood Tree page.

No interaction 2,635 drugs checked — show the list

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

Showing the 60 most looked-up of 2,635 medications checked with no known interaction — see the full Corkwood Tree list.

See the full Corkwood Tree interactions page
See every supplement checked against Chlorpheniramine, Pheylephrine, Pyrilamine, 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
Corkwood Tree monograph › Uses, safety, and every drug interaction in one place Chlorpheniramine, Pheylephrine, Pyrilamine supplement interactions › Every supplement checked against Chlorpheniramine, Pheylephrine, Pyrilamine, 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 Corkwood Tree and Chlorpheniramine, Pheylephrine, Pyrilamine Together: Common Questions

Can you take Corkwood Tree with Chlorpheniramine, Pheylephrine, Pyrilamine?
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 Corkwood Tree and Chlorpheniramine, Pheylephrine, Pyrilamine 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, Pheylephrine, Pyrilamine and Corkwood Tree?

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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.