Ceylon Leadwort + Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine
Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine brand name: Conar-A.
Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine falls into 4 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 reportCeylon Leadwort and Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine
These two interact in 4 distinct ways. Each one is explained separately below.
Why Are There 4 Interactions?
Ceylon Leadwort interacts with whole categories of medication. Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine falls into 4 of those categories, so it can interact with Ceylon Leadwort in 4 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).
CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES
1 of 4Why this applies to Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine
Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group Ceylon Leadwort interacts with.
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.
In this combo cough-and-cold product, the piece that matters here is the dextromethorphan (the cough suppressant). Your body clears it mainly through a liver enzyme called CYP2D6. Ceylon Leadwort contains plumbagin, which in lab dishes appears to slow that enzyme down. If that happened in a real person, dextromethorphan could build up a bit and lead to more drowsiness, dizziness, or a foggy, restless feeling. The acetaminophen, guaifenesin, and phenylephrine aren't really affected by this pathway.
I want to be honest about the strength here: this is only test-tube evidence and has never been seen in actual people, so the real-world risk is likely small. Still, since the plant itself can be harsh, please check with your pharmacist or doctor before pairing the two.
- 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
CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES
2 of 4Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine also falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES.
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.
Here's the honest picture with this cold and cough combo. A compound in Ceylon Leadwort called plumbagin can slow down a liver enzyme known as CYP1A2, at least in test-tube studies. None of the four ingredients in Conar-A (acetaminophen, dextromethorphan, guaifenesin, and phenylephrine) rely heavily on CYP1A2 to be cleared, so for this particular product the concern is pretty small.
In theory, if any clearance did slow, you might notice a bit more of the usual effects, like drowsiness or dizziness from dextromethorphan. But remember, this is based only on lab data, not real people. I wouldn't lose sleep over it. Still, run it by your pharmacist before combining them, especially since this supplement isn't well studied in humans.
- 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
CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES
3 of 4Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.
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.
Here's the gist with this combo cold-and-cough product. A compound in Ceylon Leadwort called plumbagin has been shown, only in test-tube studies, to slow down an enzyme called CYP3A4. The piece of your medicine most affected would be the dextromethorphan (the cough suppressant), which partly relies on that pathway. In theory, blocking the enzyme could let dextromethorphan build up a bit, which might mean more drowsiness, dizziness, or feeling foggy.
That said, this is still a lab-only finding, and it hasn't been seen in real people, so I wouldn't lose sleep over it. The acetaminophen, guaifenesin, and phenylephrine aren't meaningfully affected here. Still, since this is short-term cold relief, it's worth a quick word with your pharmacist before mixing in the supplement.
- 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
CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES
4 of 4Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine also falls under CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES.
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.
Here's the piece that matters in this combination cold-and-cough product: the acetaminophen. Your liver uses an enzyme called CYP2E1 to handle a small slice of acetaminophen, and that pathway happens to be the one that creates a toxic byproduct. In lab dishes, the plumbagin in Ceylon Leadwort appears to slow CYP2E1 down. The other ingredients (dextromethorphan, guaifenesin, phenylephrine) aren't really cleared this way, so they're not the concern here.
The honest truth is this has only been seen in test tubes, never in actual people, so I wouldn't lose sleep over it. Theoretically, blocking that enzyme could shift how acetaminophen is broken down. The bigger, well-known rule still applies: stay within the daily acetaminophen limit and don't double up on products. Run it by your pharmacist before combining them.
- 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.
Clinically significant. Avoid the combination, or use only under close professional supervision.
Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.
Generally not serious. Be aware of it and mention it to your pharmacist.
- 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.
- 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.
Ceylon Leadwort Also Interacts With Other Medications
Ceylon Leadwort has 1,096 moderate known drug interactions in our database — the Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine one above is among them. If you take anything else, check it against the full list below.
Check Another of Your Medications Against Ceylon Leadwort
We haven’t checked that one against Ceylon Leadwort yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Ceylon Leadwort. Pick one to open its full report.
See Every Supplement That Interacts With Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine
This page covers Ceylon Leadwort only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine page lists 261 supplements it has a documented interaction with, worst first, each one explained.
The most serious there right now: Activated Charcoal (major), Asarabacca (major), Beer (major), Ephedra (major) and Grapefruit (major).
By severity: 12 major · 206 moderate · 43 minor.
From our pharmacist’s overview on the Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine page
“Picture the week someone takes Conar-A (acetaminophen, dextromethorphan, guaifenesin, phenylephrine): a miserable cold, coffee to push through, maybe wine at night or an herbal remedy on top. Those habits are exactly where this list turns serious.”
Reviewed by 2 · Jul 18, 2026
Open the Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine interaction page
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 Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine 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:
Where Ceylon Leadwort and Acetaminophen, Dextromethorphan, Guaifenesin, 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.
#511 of 1,452 supplements looked up here in the last 7 days
#421 of 2,830 medications looked up here in the last 7 days
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.
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.
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.
No drugs match “”.
1,096 interactions
- Diclofenac Sodium ›
- Diltiazem ›
- Theophylline ›
- Nifedipine ›
- Ibuprofen ›
- Aspirin ›
- Hydrocortisone ›
- Insulin (rdna) ›
- Naproxen ›
- Erythromycin ›
- Estradiol ›
- Minocycline ›
- Propranolol ›
- Lidocaine ›
- Norethindrone ›
- Testosterone ›
- Verapamil ›
- Levonorgestrel ›
- Prednisone ›
- Quinidine ›
- Cyclosporine ›
- Dexamethasone ›
- Glyburide ›
- Insulin (pork) ›
- Triazolam ›
- Zopiclone ›
- Bupropion ›
- Colchicine ›
- Fentanyl ›
- Flurbiprofen ›
- Orphenadrine ›
- Oxybutynin ›
- Oxycodone ›
- Phenytoin ›
- Prednisolone ›
- Tacrolimus ›
- Temazepam ›
- Triamcinolone ›
- Budesonide ›
- Carbamazepine ›
- Clindamycin ›
- Dextromethorphan ›
- Diclofenac Potassium ›
- Dipyridamole ›
- Doxorubicin ›
- Fluticasone ›
- Formoterol ›
- Indomethacin ›
- Insulin (human) ›
- Miconazole ›
- Morphine Sulfate ›
- Trimipramine ›
- Acetaminophen ›
- Amphetamine ›
- Buprenorphine ›
- Conjugated Estrogens ›
- Diazepam ›
- Everolimus ›
- Ivabradine ›
- Ketoprofen ›
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.
- Levothyroxine ›
- Methylphenidate ›
- Ivermectin ›
- Rosuvastatin ›
- Escitalopram ›
- Docusate ›
- Hydroxyurea ›
- Valacyclovir ›
- Sumatriptan ›
- Amoxicillin ›
- Lisinopril ›
- Methotrexate ›
- Isotretinoin ›
- Acyclovir ›
- Doxycycline ›
- Pregabalin ›
- Lamotrigine ›
- Azithromycin ›
- Gabapentin ›
- Methylene Blue ›
- Ciprofloxacin ›
- Levothyroxine, Liothyronine ›
- Candesartan Cilexetil ›
- Acetaminophen, Dextromethorphan, Doxylamine ›
- Cyclopentolate ›
- Cephalexin ›
- Amoxicillin, Clavulanate Potassium ›
- Mannitol ›
- Roxithromycin ›
- Levetiracetam ›
- Ezetimibe ›
- Levothyroxine Sodium ›
- Phentermine, Topiramate ›
- Dexmethylphenidate ›
- Pegunigalsidase Alfa-iwxj ›
- Spironolactone ›
- Thyroid Hormone ›
- Daptomycin ›
- Carbidopa, Levodopa ›
- Mitomycin ›
- Hexobarbitone ›
- Levodopa ›
- Factor 7a ›
- Cefaclor ›
- Minoxidil ›
- Bentoquatam ›
- Azelaic Acid ›
- Hethylphenidate Hcl ›
- Pizotifen ›
- Phenylephrine ›
- Lenvatinib ›
- Hydroxychloroquine ›
- Salbutamol Sulfate ›
- Rocuronium ›
- Flutemetamol F-18 ›
- Alglucosidase Alpha ›
- Ribavirin Aerosol ›
- Procainamide ›
- Digoxin ›
- Vancomycin ›
Showing the 60 most looked-up of 1,733 medications checked with no known interaction — see the full Ceylon Leadwort list.
Sources & How We Checked
Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for vitamins, herbs and supplements — the basis for our interaction data.
- MedlinePlus, U.S. National Library of Medicine — NIH consumer drug information, used for the medication overviews.
- NIH Dietary Supplement Label Database (DSLD) — Official supplement product labels.
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
Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine Is Linked to Lower Levels of One Nutrient
Natural Medicines records Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine as a medicine that can lower these. This is not an interaction with Ceylon Leadwort — it is a separate effect of the medicine, and it is a reason some people are advised to supplement rather than to avoid one:
Depletion records come from the licensed Natural Medicines database. Do not start a supplement on the strength of this page — ask your pharmacist or doctor whether it applies to you.
Taking Ceylon Leadwort and Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine Together: Common Questions
Can you take Ceylon Leadwort with Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine?
Why are there 4 interactions listed for Ceylon Leadwort and Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine?
How serious is the Ceylon Leadwort and Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine interaction?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
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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.