Phellodendron + Aspirin, Codeine Phosphate, Methocarbamol
Aspirin, Codeine Phosphate, Methocarbamol brand name: Robaxisal C.
Aspirin, Codeine Phosphate, Methocarbamol falls into 3 drug categories that Phellodendron can interact with; the most serious is rated moderate. Theoretically, phellodendron might increase the sedative effects of CNS depressants.
Read the full interaction reportPhellodendron and Aspirin, Codeine Phosphate, Methocarbamol
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. Aspirin, Codeine Phosphate, Methocarbamol 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).
CNS DEPRESSANTS
1 of 3Why this applies to Aspirin, Codeine Phosphate, Methocarbamol
Aspirin, Codeine Phosphate, Methocarbamol falls under CNS DEPRESSANTS — the group Phellodendron interacts with.
Phellodendron contains berberine. Animal research suggests that berberine may have sedative effects. Theoretically, phellodendron might also have CNS depressants effects.
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.
This combination pill (Robaxisal C) already has two ingredients that can make you drowsy: codeine (an opioid pain reliever) and methocarbamol (a muscle relaxant). Phellodendron contains berberine, and in animal studies berberine has shown some sedative activity. So the worry here is simple addition: stacking a possibly calming herb on top of two medicines that already slow you down.
If they add together, you might feel extra sleepy, foggy, dizzy, or unsteady, and in larger amounts opioids can slow your breathing. I want to be honest though, this is a theoretical concern based on pharmacology and animal data, not strong human proof. Still, please check with your pharmacist or doctor before pairing them, and never drive until you know how you react.
- Janbaz KH, Gilani AH. Studies on preventive and curative effects of berberine on chemical-induced hepatotoxicity in rodents. Fitoterapia 2000;71:25-33.. PubMed
- Shanbhag, S. M., Kulkarni, H. J., and Gaitonde, B. B. Pharmacological actions of berberine on the central nervous system. Jpn.J Pharmacol 1970;20(4):482-487. PubMed
- Peng, W. H., Hsieh, M. T., and Wu, C. R. Effect of long-term administration of berberine on scopolamine-induced amnesia in rats. Jpn J Pharmacol 1997;74(3):261-266. DOI
- Sabir M and Bhide NK. Study of some pharmacological actions of berberine. Ind J Physiol & Pharmac 1971;15(3):111-132.
CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES
2 of 3Aspirin, Codeine Phosphate, Methocarbamol also falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES.
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.
Here's the wrinkle with this combination. Your tablet contains codeine, which is a prodrug. That means it doesn't do much on its own. Your body uses an enzyme called CYP2D6 to convert codeine into morphine, which is what actually relieves pain. Phellodendron contains berberine, which lab and early human data suggest can block CYP2D6.
So in this case, slowing that enzyme could mean less codeine gets turned into morphine, leaving you with weaker pain relief rather than more. The aspirin and methocarbamol parts aren't the concern here. Keep in mind this is theoretical, based on pharmacology rather than strong studies, so it may not amount to much. Still, mention it to your pharmacist or doctor before pairing the two.
- 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
ANTICOAGULANT/ANTIPLATELET DRUGS
3 of 3Aspirin, Codeine Phosphate, Methocarbamol also falls under ANTICOAGULANT/ANTIPLATELET DRUGS.
Phellodendron contains berberine. In vitro and in vivo research suggest that berberine can inhibit platelet aggregation. Theoretically, phellodendron might also inhibit platelet aggregation.
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.
This combination product contains aspirin, which is the piece that matters here. Aspirin already thins the blood by blocking your platelets from clumping together. Phellodendron contains berberine, and lab and animal studies hint that it may also slow platelets down. Stack the two and, in theory, you could bleed a little more easily than aspirin alone.
What might that look like? Easier bruising, nosebleeds, bleeding gums, or a cut that takes longer to stop. I want to be honest though: this concern comes only from test tube and animal research, not human studies, so it is more theoretical than proven. Still, since you are already on aspirin, it is worth a quick chat with your pharmacist or doctor before adding Phellodendron, especially if you have any other bleeding risks.
- Wu, J. F. and Liu, T. P. [Effects of berberine on platelet aggregation and plasma levels of TXB2 and 6-keto-PGF1 alpha in rats with reversible middle cerebral artery occlusion]. Yao Xue.Xue.Bao. 1995;30(2):98-102.
- Tripathi YB and Shukla SD. Berberis artistata inhibits PAF induced aggregation of rabbit platelets. Phytotherapy Research 1996;10:628-630.
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 Aspirin, Codeine Phosphate, Methocarbamol 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 Aspirin, Codeine Phosphate, Methocarbamol
This page covers Phellodendron only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Aspirin, Codeine Phosphate, Methocarbamol page lists 328 supplements it has a documented interaction with, worst first, each one explained.
The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Asarabacca (major), Beer (major) and Danshen (major).
By severity: 12 major · 282 moderate · 34 minor.
From our pharmacist’s overview on the Aspirin, Codeine Phosphate, Methocarbamol page
“Alcohol is the single riskiest thing to combine with Robaxisal C (aspirin, codeine phosphate, and methocarbamol). Beer and wine both carry major ratings backed by solid human evidence, because codeine and methocarbamol already slow breathing and reflexes, and alcohol deepens that sedation.”
Reviewed by 2 · Jul 18, 2026
Open the Aspirin, Codeine Phosphate, Methocarbamol 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 Aspirin, Codeine Phosphate, Methocarbamol 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 Aspirin, Codeine Phosphate, Methocarbamol 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.
#287 of 1,452 supplements looked up here in the last 7 days
#544 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 ›
- Thyroid Hormone ›
- Carbidopa, Levodopa ›
- Mitomycin ›
- Levodopa ›
- Ezetimibe ›
- Cefaclor ›
- Lenvatinib ›
- Phenylephrine ›
- Vancomycin ›
- Hethylphenidate Hcl ›
- Dirithromycin ›
- Bentoquatam ›
- Amoxicillin, Clavulanate Potassium ›
- Procainamide ›
- Hydroxychloroquine ›
- Digoxin ›
- Azelaic Acid ›
- Triptorelin ›
- Dextrothyroxine ›
- Lomustine ›
- Tocainide ›
- Pizotifen ›
- Rocuronium ›
- Succimer ›
- Mitomycin C ›
- Paracetamol ›
- Halothane ›
- Desflurane ›
- Chenodiol ›
- Gestodene ›
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
Aspirin, Codeine Phosphate, Methocarbamol Is Linked to Lower Levels of 3 Nutrients
Natural Medicines records Aspirin, Codeine Phosphate, Methocarbamol 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:
Read the full Aspirin, Codeine Phosphate, Methocarbamol nutrient depletion report ›
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 Aspirin, Codeine Phosphate, Methocarbamol Together: Common Questions
Can you take Phellodendron with Aspirin, Codeine Phosphate, Methocarbamol?
Why are there 3 interactions listed for Phellodendron and Aspirin, Codeine Phosphate, Methocarbamol?
How serious is the Phellodendron and Aspirin, Codeine Phosphate, Methocarbamol interaction?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Still Have a Question About Aspirin, Codeine Phosphate, Methocarbamol and Phellodendron?
Our pharmacists answer your medication & supplement questions — free.
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.