Drug & supplement interaction

Ceylon Leadwort + Dextromethorphan, Guaifenesin, Pseudophedrine

Dextromethorphan, Guaifenesin, Pseudophedrine brand names: Organidin NR, Anatuss DM.

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

Dextromethorphan, Guaifenesin, Pseudophedrine falls into 2 drug categories that Ceylon Leadwort can interact with; the most serious is rated moderate. Plumbagin, a constituent of Ceylon leadwort, has been shown to inhibit cytochrome P450 2D6 (CYP2D6) in vitro.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Ceylon Leadwort and Dextromethorphan, Guaifenesin, Pseudophedrine

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Ceylon Leadwort interacts with whole categories of medication. Dextromethorphan, Guaifenesin, Pseudophedrine falls into 2 of those categories, so it can interact with Ceylon Leadwort in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

1 of 2

Why this applies to Dextromethorphan, Guaifenesin, Pseudophedrine

Dextromethorphan, Guaifenesin, Pseudophedrine falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group Ceylon Leadwort interacts with.

Plumbagin, a constituent of Ceylon leadwort, has been shown to inhibit cytochrome P450 2D6 (CYP2D6) in vitro. So far, this interaction has not been reported in humans. Theoretically, Ceylon leadwort might increase the levels of drugs metabolized by CYP2D6. Some drugs metabolized by CYP2D6 include amitriptyline (Elavil), codeine, desipramine (Norpramin), flecainide (Tambocor), fluoxetine (Prozac), ondansetron (Zofran), tramadol (Ultram), and others.
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

In this combo cough and cold product, the piece that matters here is dextromethorphan. Your body relies on an enzyme called CYP2D6 to clear it. Lab studies suggest plumbagin (a compound in Ceylon Leadwort) can block that enzyme, which in theory would let dextromethorphan build up a bit higher than usual.

If that happened, you might notice more of dextromethorphan's typical effects, like drowsiness, dizziness, or feeling a little foggy or unsteady. Keep in mind this is based only on test-tube research and has not been seen in real people, so I wouldn't lose sleep over it. The guaifenesin and pseudoephedrine parts aren't really affected by this pathway. Still, before pairing them, it's worth a quick chat with your pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Chen A, Zhou X, Tang S, Liu M, Wang X. Evaluation of the inhibition potential of plumbagin against cytochrome P450 using LC-MS/MS and cocktail approach. Sci Rep. 2016 Jun 22;6:28482. PubMed
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 2

Dextromethorphan, Guaifenesin, Pseudophedrine also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Plumbagin, a constituent of Ceylon leadwort, has been shown to inhibit cytochrome P450 3A4 (CYP3A4) in vitro. So far, this interaction has not been reported in humans. Theoretically, Ceylon leadwort might increase the levels of drugs metabolized by CYP3A4. Some drugs metabolized by CYP3A4 include lovastatin (Mevacor), clarithromycin (Biaxin), indinavir (Crixivan), sildenafil (Viagra), triazolam (Halcion), and numerous others.
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 with this cough and cold combo (dextromethorphan, guaifenesin, and pseudoephedrine). Ceylon Leadwort contains a compound called plumbagin, which in lab dish studies appears to slow down a liver enzyme called CYP3A4. Dextromethorphan is partly handled by that enzyme, so in theory the leadwort could let dextromethorphan build up a bit. That might mean more of its usual effects, like drowsiness, dizziness, or feeling foggy.

I want to be honest though: this has only been seen in test tubes, never in real people, so it's a theoretical concern, not a proven one. Guaifenesin and pseudoephedrine aren't really affected here. To be safe, just run it by your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Chen A, Zhou X, Tang S, Liu M, Wang X. Evaluation of the inhibition potential of plumbagin against cytochrome P450 using LC-MS/MS and cocktail approach. Sci Rep. 2016 Jun 22;6:28482. 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

Ceylon Leadwort Also Interacts With Other Medications

Ceylon Leadwort has 1,096 moderate known drug interactions in our database — the Dextromethorphan, Guaifenesin, Pseudophedrine one above is among them. If you take anything else, check it against the full list below.

Moderate 1,096 No known interaction 1,734 (incl. Dextromethorphan, Guaifenesin, Pseudophedrine)
Taking anything else?

Check Another of Your Medications Against Ceylon Leadwort

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

Everything else you take

See Every Supplement That Interacts With Dextromethorphan, Guaifenesin, Pseudophedrine

This page covers Ceylon Leadwort only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Dextromethorphan, Guaifenesin, Pseudophedrine page lists 171 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Lithium (major), St. John's Wort (major) and 1,3-dmaa (moderate).

By severity: 4 major · 125 moderate · 42 minor.

Open the Dextromethorphan, Guaifenesin, Pseudophedrine interaction page

One more smart check

Taking Ceylon Leadwort as Part of a Dietary Supplement Product? Check It for Interactions

We hold 96 real supplement products containing Ceylon Leadwort, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Ceylon Leadwort. Your product may carry other ingredients that interact with Dextromethorphan, Guaifenesin, Pseudophedrine too, on top of Ceylon Leadwort — 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 Ceylon Leadwort and Dextromethorphan, Guaifenesin, Pseudophedrine 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 Ceylon Leadwort
Top half

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

29 days ago today
Medication Dextromethorphan, Guaifenesin, Pseudophedrine
Steady interest

#2,450 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 Ceylon Leadwort

What is Ceylon Leadwort?

  • Digestive complaints and poor appetite
  • Skin conditions and wounds (applied to the skin)
  • Joint pain and swelling
  • Traditional 'metabolism-boosting' tonics
  • Antimicrobial folk remedy

Ceylon Leadwort (Plumbago zeylanica) is a plant long used in Ayurvedic and other traditional medicine systems, mainly for digestion, skin problems, and pain. Solid human studies are lacking, and the plant contains plumbagin, a compound that can irritate skin and tissues and may be unsafe in larger amounts. Talk to a pharmacist or doctor before using it, and avoid it in pregnancy.

Read the full Ceylon Leadwort monograph & all interactions
Keep checking

Other Drugs & Ceylon Leadwort

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

0Major
1,096Moderate
0Minor
1,733No known interaction
1,096 Moderate 1,733 No interaction
Moderate

1,096 interactions

Showing 60 of 1,096 moderate interactions — see all 1,096 on the Ceylon Leadwort page.

No interaction 1,733 drugs checked — show the list

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

Showing the 60 most looked-up of 1,733 medications checked with no known interaction — see the full Ceylon Leadwort list.

See the full Ceylon Leadwort interactions page
See every supplement checked against Dextromethorphan, Guaifenesin, Pseudophedrine, 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
Ceylon Leadwort monograph › Uses, safety, and every drug interaction in one place Dextromethorphan, Guaifenesin, Pseudophedrine supplement interactions › Every supplement checked against Dextromethorphan, Guaifenesin, Pseudophedrine, 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 Ceylon Leadwort and Dextromethorphan, Guaifenesin, Pseudophedrine Together: Common Questions

Can you take Ceylon Leadwort with Dextromethorphan, Guaifenesin, Pseudophedrine?
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.
Why are there 2 interactions listed for Ceylon Leadwort and Dextromethorphan, Guaifenesin, Pseudophedrine?
Dextromethorphan, Guaifenesin, Pseudophedrine belongs to more than one drug category, and Ceylon Leadwort interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Ceylon Leadwort and Dextromethorphan, Guaifenesin, Pseudophedrine 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 Dextromethorphan, Guaifenesin, Pseudophedrine and Ceylon Leadwort?

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.