Drug & supplement interaction

Corkwood Tree + Promethazine, Pseudoephedrine

Promethazine, Pseudoephedrine brand name: Phenergan D.

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

Corkwood Tree has a moderate interaction with Promethazine, Pseudoephedrine. 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?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Corkwood Tree and Promethazine, Pseudoephedrine

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

Moderate

ANTICHOLINERGIC DRUGS

Why this applies to Promethazine, Pseudoephedrine

Promethazine, Pseudoephedrine 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 about Phenergan D: the promethazine part already has its own anticholinergic action. It dries you up and calms nausea, but it can also cause dry mouth, blurred vision, constipation, trouble urinating, drowsiness, and a fast heartbeat. Corkwood tree carries scopolamine and atropine, which work the very same way. Stack them together and those effects can pile up rather than cancel out.

This concern is theoretical, based on how these chemicals behave, so we don't have strong studies proving it. Still, the raw plant is genuinely toxic, so I wouldn't combine it with this medicine. The pseudoephedrine could add to the racing-heart feeling too. Please check with your pharmacist or doctor before mixing them.

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 Promethazine, Pseudoephedrine 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. Promethazine, Pseudoephedrine)
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 Promethazine, Pseudoephedrine

This page covers Corkwood Tree only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Promethazine, Pseudoephedrine page lists 116 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Ephedra (major), Henbane (major), Peyote (major) and Rauvolfia Vomitoria (major).

By severity: 7 major · 93 moderate · 16 minor.

From our pharmacist’s overview on the Promethazine, Pseudoephedrine page

“Phenergan D combines a sedating antihistamine, promethazine, with the decongestant stimulant pseudoephedrine, and its supplement list pulls hard in both directions, so this is one to treat with genuine care. The biggest cluster, from everyday caffeine sources like coffee and cola nut up to ephedra, stacks extra stimulation on the pseud…”

Reviewed by 2 · Jul 18, 2026

Open the Promethazine, Pseudoephedrine interaction page

How much people look this up

Where Corkwood Tree and Promethazine, Pseudoephedrine 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

#1,088 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Promethazine, Pseudoephedrine
Top half

#1,348 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 Promethazine, Pseudoephedrine, 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 Promethazine, Pseudoephedrine supplement interactions › Every supplement checked against Promethazine, Pseudoephedrine, 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 Promethazine, Pseudoephedrine Together: Common Questions

Can you take Corkwood Tree with Promethazine, Pseudoephedrine?
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 Promethazine, Pseudoephedrine 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 Promethazine, Pseudoephedrine and Corkwood Tree?

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.