Phellodendron + Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine
Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine brand name: Theracaps.
Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine falls into 3 drug categories that Phellodendron can interact with; the most serious is rated moderate. Theoretically, phellodendron might increase serum levels of drugs metabolized by CYP2D6.
Read the full interaction reportPhellodendron and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine
These two interact in 3 distinct ways. Each one is explained separately below.
Why Are There 3 Interactions?
Phellodendron interacts with whole categories of medication. Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine falls into 3 of those categories, so it can interact with Phellodendron in 3 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 3Why this applies to Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine
Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group Phellodendron interacts with.
Phellodendron contains berberine. In vitro research and preliminary clinical evidence show that berberine can inhibit CYP2D6. Theoretically, phellodendron might also inhibit CYP2D6.
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.
Your cold and cough combo (Theracaps) contains dextromethorphan, and that's the piece that matters here. Dextromethorphan is cleared by a liver enzyme called CYP2D6. The berberine in phellodendron may slow that enzyme down, so in theory dextromethorphan could build up a bit higher than usual. If that happens, you might notice more drowsiness, dizziness, or a feeling of being foggy or restless.
I want to be honest about the strength of this: it's theoretical, based mostly on lab work, not solid human studies. For most people it's unlikely to cause real trouble, but if you take phellodendron regularly or feel unusually woozy, check in with your pharmacist or doctor before combining them. Don't stop anything on your own.
- Chatterjee P, Franklin MR. Human cytochrome p450 inhibition and metabolic-intermediate complex formation by goldenseal extract and its methylenedioxyphenyl components. Drug Metab Dispos 2003;31:1391-7. PubMed
- Guo, Y., Chen, Y., Tan, Z. R., Klaassen, C. D., and Zhou, H. H. Repeated administration of berberine inhibits cytochromes P450 in humans. Eur J Clin Pharmacol 2012;68(2):213-217. PubMed
- Hermann, R. and von, Richter O. Clinical evidence of herbal drugs as perpetrators of pharmacokinetic drug interactions. Planta Med 2012;78(13):1458-1477. PubMed
CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES
2 of 3Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.
Phellodendron contains berberine. In vitro research and preliminary clinical research show that berberine moderately inhibits CYP3A4. Theoretically, phellodendron might also inhibit CYP3A4.
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.
Theracaps is a combo cold product, and one of its ingredients, dextromethorphan (the cough suppressant), is partly handled by a liver enzyme called CYP3A4. Phellodendron contains berberine, which lab and early studies suggest can mildly slow that same enzyme. In theory, that could let a little more dextromethorphan build up, which might mean more drowsiness, dizziness, or feeling foggy. The other pieces (acetaminophen, the decongestant, and the antihistamine) aren't strongly tied to this pathway here.
Keep in mind this is a theoretical concern based mostly on lab work, not proven harm in people, so it's usually not something to panic over. Still, since this is a short-term cold product, it's worth a quick chat with your pharmacist before combining them.
- Wu X, Li Q, Xin H, Yu A, Zhong M. Effects of berberine on the blood concentration of cyclosporin A in renal transplanted recipients: clinical and pharmacokinetic study. Eur J Clin Pharmacol 2005;61:567-72. PubMed
- Budzinski JW, Foster BC, Vandenhoek S, Arnason JT. An in vitro evaluation of human cytochrome P450 3A4 inhibition by selected commercial herbal extracts and tinctures. Phytomedicine 2000;7:273-82. PubMed
- Guo, Y., Chen, Y., Tan, Z. R., Klaassen, C. D., and Zhou, H. H. Repeated administration of berberine inhibits cytochromes P450 in humans. Eur J Clin Pharmacol 2012;68(2):213-217. PubMed
- Hermann, R. and von, Richter O. Clinical evidence of herbal drugs as perpetrators of pharmacokinetic drug interactions. Planta Med 2012;78(13):1458-1477. PubMed
DEXTROMETHORPHAN (Robitussin DM, others)
3 of 3Phellodendron contains berberine. Preliminary clinical research shows that berberine can inhibit cytochrome P450 2D6 (CYP2D6) activity and reduce the metabolism of dextromethorphan. Theoretically, phellodendron may also inhibit the metabolism of dextromethorphan.
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.
Your Theracaps product is a combo cold remedy, and the piece that matters here is the dextromethorphan (the cough suppressant). Your body clears dextromethorphan using a liver enzyme called CYP2D6. Phellodendron contains berberine, which lab and early human studies suggest can slow that same enzyme down. If it does, dextromethorphan can build up a bit higher than usual.
In real life that might mean more of dextromethorphan's typical effects, like drowsiness, dizziness, or feeling foggy or lightheaded. I want to be honest though: this is a theoretical concern based on how these compounds behave, not strong proof in people. The other ingredients (acetaminophen, phenylpropanolamine, pyrilamine) aren't the focus of this interaction. If you'd like to use both, just run it by your pharmacist or doctor first.
- Guo, Y., Chen, Y., Tan, Z. R., Klaassen, C. D., and Zhou, H. H. Repeated administration of berberine inhibits cytochromes P450 in humans. Eur J Clin Pharmacol 2012;68(2):213-217. 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.
Phellodendron Also Interacts With Other Medications
Phellodendron has 1,159 moderate known drug interactions in our database — the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine one above is among them. If you take anything else, check it against the full list below.
Check Another of Your Medications Against Phellodendron
We haven’t checked that one against Phellodendron yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Phellodendron. Pick one to open its full report.
See Every Supplement That Interacts With Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine
This page covers Phellodendron only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine page lists 282 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: 14 major · 223 moderate · 45 minor.
From our pharmacist’s overview on the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine page
“Of everything on this page, ephedra worries me most for anyone using Theracaps (acetaminophen, dextromethorphan, phenylpropanolamine, and pyrilamine), because the decongestant in this cold formula is itself a stimulant. Adding ephedra or any of the 44 stimulant entries can push blood pressure and heart rate to unsafe levels.”
Reviewed by 2 · Jul 18, 2026
Open the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine interaction page
Taking Phellodendron as Part of a Dietary Supplement Product? Check It for Interactions
We hold 393 real supplement products containing Phellodendron, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Phellodendron. Your product may carry other ingredients that interact with Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine too, on top of Phellodendron — and those would not show on this page. Find your product and we’ll check every ingredient on its label:
Where Phellodendron and Acetaminophen, Dextromethorphan, Phenylpropanolamine, 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.
#317 of 1,452 supplements looked up here in the last 7 days
#1,446 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 Phellodendron
What is Phellodendron?
- Digestive complaints and diarrhea
- Inflammation and joint discomfort
- Stress and weight management (in combination products)
- Skin conditions (topical, traditional)
- Antimicrobial support
Phellodendron is a traditional Chinese medicine bark (Huang Bai) that contains berberine and other plant compounds with antimicrobial and anti-inflammatory activity in lab studies. Human evidence for most uses is limited, and it is often sold in combination with other herbs, making its individual effects hard to judge. Talk with your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.
Other Drugs & Phellodendron
Browse every other medication we’ve checked against Phellodendron — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
1,159 interactions
- Diclofenac Sodium ›
- Diltiazem ›
- Nifedipine ›
- Ibuprofen ›
- Diphenhydramine ›
- Aspirin ›
- Hydrocortisone ›
- Insulin (rdna) ›
- Naproxen ›
- Erythromycin ›
- Estradiol ›
- Minocycline ›
- Propranolol ›
- Lidocaine ›
- Guaifenesin ›
- Hydrochlorothiazide ›
- Norethindrone ›
- Testosterone ›
- Verapamil ›
- Levonorgestrel ›
- Prednisone ›
- Quinidine ›
- Cyclosporine ›
- Dexamethasone ›
- Flurazepam ›
- Glyburide ›
- Insulin (pork) ›
- Triazolam ›
- Zopiclone ›
- Colchicine ›
- Fentanyl ›
- Flurbiprofen ›
- Oxybutynin ›
- Oxycodone ›
- Phenytoin ›
- Prednisolone ›
- Tacrolimus ›
- Temazepam ›
- Budesonide ›
- Carbamazepine ›
- Clindamycin ›
- Dextromethorphan ›
- Diclofenac Potassium ›
- Dipyridamole ›
- Doxorubicin ›
- Fluticasone ›
- Formoterol ›
- Hydralazine ›
- Indomethacin ›
- Insulin (human) ›
- Miconazole ›
- Morphine Sulfate ›
- Nitrazepam ›
- Trimipramine ›
- Amphetamine ›
- Buprenorphine ›
- Conjugated Estrogens ›
- Diazepam ›
- Everolimus ›
- Ivabradine ›
Showing 60 of 1,159 moderate interactions — see all 1,159 on the Phellodendron page.
No interaction 1,670 drugs checked — show the list
We also checked Phellodendron against these medications and found no known interaction in our sources. Open any page to confirm.
- Levothyroxine ›
- Methylphenidate ›
- Ivermectin ›
- Rosuvastatin ›
- Escitalopram ›
- Acetaminophen ›
- Docusate ›
- Valacyclovir ›
- Hydroxyurea ›
- Sumatriptan ›
- Bupropion ›
- Amoxicillin ›
- Acyclovir ›
- Bendamustine ›
- Doxycycline ›
- Methotrexate ›
- Azithromycin ›
- Isotretinoin ›
- Methylene Blue ›
- Ciprofloxacin ›
- Levothyroxine, Liothyronine ›
- Cyclopentolate ›
- Cephalexin ›
- Roxithromycin ›
- Pegunigalsidase Alfa-iwxj ›
- Daptomycin ›
- Hexobarbitone ›
- Levothyroxine Sodium ›
- Dexmethylphenidate ›
- Factor 7a ›
- Carbidopa, Levodopa ›
- Thyroid Hormone ›
- Mitomycin ›
- Levodopa ›
- Ezetimibe ›
- Cefaclor ›
- Lenvatinib ›
- Phenylephrine ›
- Vancomycin ›
- Hethylphenidate Hcl ›
- Dirithromycin ›
- Bentoquatam ›
- Procainamide ›
- Amoxicillin, Clavulanate Potassium ›
- Hydroxychloroquine ›
- Digoxin ›
- Azelaic Acid ›
- Dextrothyroxine ›
- Triptorelin ›
- Lomustine ›
- Pizotifen ›
- Tocainide ›
- Rocuronium ›
- Succimer ›
- Mitomycin C ›
- Paracetamol ›
- Halothane ›
- Gestodene ›
- Chenodiol ›
- Desflurane ›
Showing the 60 most looked-up of 1,670 medications checked with no known interaction — see the full Phellodendron 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, Phenylpropanolamine, Pyrilamine Is Linked to Lower Levels of One Nutrient
Natural Medicines records Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine as a medicine that can lower these. This is not an interaction with Phellodendron — 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 Phellodendron and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine Together: Common Questions
Can you take Phellodendron with Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine?
Why are there 3 interactions listed for Phellodendron and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine?
How serious is the Phellodendron and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine 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.