Schizonepeta + Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine
Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine brand name: Conar-A.
Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine falls into 4 drug categories that Schizonepeta can interact with; the most serious is rated moderate. Animal research suggests that schizonepetin, a monoterpene constituent of schizonepeta, inhibits cytochrome P450 (CYP) 2D6.
Read the full interaction reportSchizonepeta and Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine
These two interact in 4 distinct ways. Each one is explained separately below.
Why Are There 4 Interactions?
Schizonepeta interacts with whole categories of medication. Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine falls into 4 of those categories, so it can interact with Schizonepeta 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 Schizonepeta interacts with.
Some substrates of CYP2D6 include amitriptyline (Elavil), codeine, desipramine (Norpramin), flecainide (Tambocor), haloperidol (Haldol), imipramine (Tofranil), metoprolol (Lopressor, Toprol XL), ondansetron (Zofran), paroxetine (Paxil), risperidone (Risperdal), tramadol (Ultram), venlafaxine (Effexor), and others.
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 cold product, the piece that matters here is the dextromethorphan (the cough suppressant). Your body clears it using a liver enzyme called CYP2D6. Lab and animal studies hint that a compound in Schizonepeta may slow that enzyme down. If it does, dextromethorphan could build up a bit and lead to stronger effects like drowsiness, dizziness, or feeling foggy. The acetaminophen, guaifenesin, and phenylephrine aren't really affected by this pathway.
Honestly, this is a theoretical concern based only on early research, not real-world cases, so I wouldn't lose sleep over it. Still, before pairing them, it's worth a quick chat with your pharmacist or doctor, especially if you take other medicines too.
- Bao B, Geng T, Cao Y, et al. Effects of schizonepetin on activity of mRNA expression of cytochrome P450 enzymes in rats. Int J Mol Sci. 2012;13(12):17006-18.
CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES
2 of 4Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine also falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES.
Some substrates of CYP1A2 include clozapine (Clozaril), cyclobenzaprine (Flexeril), fluvoxamine (Luvox), haloperidol (Haldol), imipramine (Tofranil), mexiletine (Mexitil), olanzapine (Zyprexa), pentazocine (Talwin), propranolol (Inderal), tacrine (Cognex), theophylline, zileuton (Zyflo), zolmitriptan (Zomig), and others.
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 practical side of this one. This cold and cough combo contains four ingredients, but the only one that really leans on the liver enzyme in question (CYP1A2) is acetaminophen, and even that's a minor pathway. The concern is theoretical: in animal and lab studies, a compound in Schizonepeta appears to slow CYP1A2. If that happened in people, a drug cleared by that enzyme could build up a bit, which in acetaminophen's case is mainly a question of liver strain rather than feeling more drowsy or jittery.
Honestly, this is weak, indirect evidence, so I wouldn't lose sleep over it. Just don't stack on extra acetaminophen from other products, go easy on alcohol, and check with your pharmacist if you plan to use Schizonepeta regularly.
- Bao B, Geng T, Cao Y, et al. Effects of schizonepetin on activity of mRNA expression of cytochrome P450 enzymes in rats. Int J Mol Sci. 2012;13(12):17006-18.
CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES
3 of 4Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.
Some substrates of CYP3A4 include lovastatin (Mevacor), ketoconazole (Nizoral), itraconazole (Sporanox), fexofenadine (Allegra), triazolam (Halcion), and numerous others.
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 cold-and-cough combo (Conar-A) packs four ingredients: acetaminophen for pain and fever, dextromethorphan to quiet a cough, guaifenesin to loosen mucus, and phenylephrine as a decongestant. The concern on file is that Schizonepeta, in animal studies, may speed up a liver enzyme called CYP3A4. In theory, that could clear some of these ingredients a bit faster and make them work a touch less, so you might notice less cough relief or a weaker decongestant effect.
Honestly, this is a very weak, theory-only signal based on lab and animal data, not real people, so I wouldn't lose sleep over it. Still, since the evidence is thin and herbs vary, it's worth a quick chat with your pharmacist before combining them.
- Bao B, Geng T, Cao Y, et al. Effects of schizonepetin on activity of mRNA expression of cytochrome P450 enzymes in rats. Int J Mol Sci. 2012;13(12):17006-18.
CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES
4 of 4Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine also falls under CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES.
Some substrates of CYP2E1 include acetaminophen, chlorzoxazone (Parafon Forte), ethanol, theophylline, and anesthetics such as enflurane (Ethrane), halothane (Fluothane), isoflurane (Forane), and methoxyflurane (Penthrane).
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.
Of the four ingredients in this cold and cough combo, the one that touches this interaction is the acetaminophen (the Tylenol part). A liver enzyme called CYP2E1 helps break acetaminophen down, and in lab and animal studies a compound in Schizonepeta seems to slow that enzyme. In theory, blocking it could let a bit more acetaminophen linger in your system. That matters mostly because acetaminophen's main risk, when levels run high, is liver stress.
Keep in mind this is very weak evidence, only test-tube and animal data, so I wouldn't lose sleep over it. The bigger real-world tip is simply not to double up on acetaminophen from other products and to stay within the daily limit. If you take Schizonepeta regularly, just run it by your pharmacist or doctor first.
- Bao B, Geng T, Cao Y, et al. Effects of schizonepetin on activity of mRNA expression of cytochrome P450 enzymes in rats. Int J Mol Sci. 2012;13(12):17006-18.
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.
Schizonepeta Also Interacts With Other Medications
Schizonepeta has 796 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 Schizonepeta
We haven’t checked that one against Schizonepeta yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Schizonepeta. Pick one to open its full report.
See Every Supplement That Interacts With Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine
This page covers Schizonepeta 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 Schizonepeta as Part of a Dietary Supplement Product? Check It for Interactions
We hold 285 real supplement products containing Schizonepeta, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Schizonepeta. Your product may carry other ingredients that interact with Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine too, on top of Schizonepeta — and those would not show on this page. Find your product and we’ll check every ingredient on its label:
Where Schizonepeta 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.
#376 of 1,452 supplements looked up here in the last 7 days
#576 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 Schizonepeta
What is Schizonepeta?
- Common cold and early-stage fever
- Itchy skin rashes and hives
- Sore throat
- Headache
- Measles and other skin eruptions (traditional use)
Schizonepeta is a mint-family herb long used in traditional Chinese medicine, usually as part of combination formulas for colds, fevers, and itchy skin conditions. Modern human evidence is very limited, so its benefits are not well proven. Talk to a pharmacist or doctor before using it, especially if you are pregnant, breastfeeding, or taking other medicines.
Other Drugs & Schizonepeta
Browse every other medication we’ve checked against Schizonepeta — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
796 interactions
- Diltiazem ›
- Theophylline ›
- Nifedipine ›
- Hydrocortisone ›
- Naproxen ›
- Erythromycin ›
- Estradiol ›
- Propranolol ›
- Lidocaine ›
- Norethindrone ›
- Testosterone ›
- Verapamil ›
- Levonorgestrel ›
- Prednisone ›
- Quinidine ›
- Cyclosporine ›
- Dexamethasone ›
- Triazolam ›
- Zopiclone ›
- Colchicine ›
- Fentanyl ›
- Oxybutynin ›
- Oxycodone ›
- Prednisolone ›
- Tacrolimus ›
- Temazepam ›
- Budesonide ›
- Carbamazepine ›
- Clindamycin ›
- Dextromethorphan ›
- Doxorubicin ›
- Fluticasone ›
- Formoterol ›
- Miconazole ›
- Morphine Sulfate ›
- Acetaminophen ›
- Amphetamine ›
- Buprenorphine ›
- Conjugated Estrogens ›
- Diazepam ›
- Everolimus ›
- Ivabradine ›
- Lofepramine ›
- Medroxyprogesterone ›
- Medroxyprogesterone Acetate ›
- Nortriptyline ›
- Propoxyphene ›
- Rifampin ›
- Testosterone Undecanoate ›
- Aripiprazole ›
- Bendamustine ›
- Caffeine (otc Drug) ›
- Ciclesonide ›
- Clonazepam ›
- Cyclobenzaprine ›
- Dapsone ›
- Desipramine ›
- Doxepin ›
- Duloxetine ›
- Erythromycin Ethylsuccinate ›
Showing 60 of 796 moderate interactions — see all 796 on the Schizonepeta page.
No interaction 2,033 drugs checked — show the list
We also checked Schizonepeta against these medications and found no known interaction in our sources. Open any page to confirm.
- Levothyroxine ›
- Methylphenidate ›
- Ivermectin ›
- Aspirin ›
- Rosuvastatin ›
- Escitalopram ›
- Docusate ›
- Hydroxyurea ›
- Valacyclovir ›
- Ibuprofen ›
- Tirzepatide ›
- Semaglutide ›
- Sumatriptan ›
- Metformin ›
- Lisinopril ›
- Amoxicillin ›
- Bupropion ›
- Acyclovir ›
- Methotrexate ›
- Doxycycline ›
- Pregabalin ›
- Lamotrigine ›
- Azithromycin ›
- Gabapentin ›
- Isotretinoin ›
- Methylene Blue ›
- Ciprofloxacin ›
- Levothyroxine, Liothyronine ›
- Candesartan Cilexetil ›
- Cephalexin ›
- Cyclopentolate ›
- Acetaminophen, Dextromethorphan, Doxylamine ›
- Roxithromycin ›
- Mannitol ›
- Levetiracetam ›
- Pegunigalsidase Alfa-iwxj ›
- Ezetimibe ›
- Daptomycin ›
- Levothyroxine Sodium ›
- Dexmethylphenidate ›
- Mitomycin ›
- Amoxicillin, Clavulanate Potassium ›
- Valsartan ›
- Spironolactone ›
- Hexobarbitone ›
- Thyroid Hormone ›
- Phentermine, Topiramate ›
- Carbidopa, Levodopa ›
- Factor 7a ›
- Levodopa ›
- Minoxidil ›
- Hethylphenidate Hcl ›
- Cefaclor ›
- Lenvatinib ›
- Azelaic Acid ›
- Phenylephrine ›
- Hydroxychloroquine ›
- Tenecteplase ›
- Vancomycin ›
- Dirithromycin ›
Showing the 60 most looked-up of 2,033 medications checked with no known interaction — see the full Schizonepeta 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 Schizonepeta — 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 Schizonepeta and Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine Together: Common Questions
Can you take Schizonepeta with Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine?
Why are there 4 interactions listed for Schizonepeta and Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine?
How serious is the Schizonepeta 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.