Drug & supplement interaction

Schizonepeta + Acetaminophen, Codeine

Acetaminophen, Codeine brand names: Tylenol w/ Codeine, Tylenol No.3.

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

Acetaminophen, Codeine falls into 3 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 report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Schizonepeta and Acetaminophen, Codeine

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Schizonepeta interacts with whole categories of medication. Acetaminophen, Codeine falls into 3 of those categories, so it can interact with Schizonepeta in 3 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 3

Why this applies to Acetaminophen, Codeine

Acetaminophen, Codeine falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group Schizonepeta interacts with.

Animal research suggests that schizonepetin, a monoterpene constituent of schizonepeta, inhibits cytochrome P450 (CYP) 2D6. Theoretically, schizonepeta might increase the effects and side effects of CYP2D6 substrates.
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.
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 wrinkle with Tylenol with Codeine: the codeine part is actually a prodrug. It does very little on its own until your liver enzyme CYP2D6 converts it into morphine, which is what actually relieves pain. Schizonepeta has shown in lab and animal studies that one of its compounds may slow down CYP2D6.

If that holds true in people, you'd make less morphine from your codeine, so you could get weaker pain relief. The acetaminophen side isn't affected. Keep in mind this is only theoretical, based on animal data, so we don't really know if it matters at normal doses. Still, if your pain isn't well controlled, mention this combo to your pharmacist or doctor before changing anything.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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.
Moderate

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

2 of 3

Acetaminophen, Codeine also falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES.

Animal research suggests that schizonepetin, a monoterpene constituent of schizonepeta, inhibits cytochrome P450 (CYP) 1A2. Theoretically, schizonepeta might increase the effects and side effects of 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.
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 honest picture with Tylenol with Codeine: this interaction is only theoretical. It comes from lab and animal work showing a compound in Schizonepeta may slow an enzyme called CYP1A2. The trouble is, that enzyme isn't the main one your body uses to handle codeine or acetaminophen, so I wouldn't expect a big real-world effect here.

Codeine is actually a prodrug, meaning your body has to convert it (mostly through a different enzyme, CYP2D6) into the active painkiller. So CYP1A2 isn't really the driver for it. Still, since human data is essentially missing, it's worth a quick chat with your pharmacist or doctor before combining them, especially to watch for extra drowsiness, constipation, or stomach upset.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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.
Moderate

CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES

3 of 3

Acetaminophen, Codeine also falls under CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES.

Animal research suggests that schizonepetin, a monoterpene constituent of schizonepeta, inhibits cytochrome P450 (CYP) 2E1. Theoretically, schizonepeta might increase the effects and side effects of 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).
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 interesting part: the acetaminophen side of Tylenol with Codeine is partly handled by a liver enzyme called CYP2E1, and this enzyme is what turns a small portion of acetaminophen into a harmful byproduct. In lab and animal studies, a compound in Schizonepeta appears to slow CYP2E1 down. In theory, blocking that pathway could actually mean less of the toxic byproduct forming, but it might also let acetaminophen linger a bit longer in the body. Honestly, the human meaning here is fuzzy.

I want to be straight with you: this is based only on animal research, so it's quite theoretical and nothing to lose sleep over. Just keep your acetaminophen within safe daily limits and check with your pharmacist before adding Schizonepeta.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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.

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

Schizonepeta Also Interacts With Other Medications

Schizonepeta has 796 moderate known drug interactions in our database — the Acetaminophen, Codeine one above is among them. If you take anything else, check it against the full list below.

Moderate 796 No known interaction 2,034 (incl. Acetaminophen, Codeine)
Taking anything else?

Check Another of Your Medications Against Schizonepeta

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

Everything else you take

See Every Supplement That Interacts With Acetaminophen, Codeine

This page covers Schizonepeta only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Codeine page lists 240 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 Gamma-hydroxybutyrate (ghb) (major).

By severity: 9 major · 191 moderate · 40 minor.

From our pharmacist’s overview on the Acetaminophen, Codeine page

“People usually take Tylenol No. 3 (acetaminophen with codeine) for short-term pain, often while still drinking wine with dinner or reaching for an herbal sleep aid.”

Reviewed by 2 · Jul 18, 2026

Open the Acetaminophen, Codeine interaction page

One more smart check

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, Codeine 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:

How much people look this up

Where Schizonepeta and Acetaminophen, Codeine 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 Schizonepeta
Top 25%

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

29 days ago today
Medication Acetaminophen, Codeine
Top 5%

#59 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 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.

Read the full Schizonepeta monograph & all interactions
Keep checking

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.

0Major
796Moderate
0Minor
2,033No known interaction
796 Moderate 2,033 No interaction
Moderate

796 interactions

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.

Showing the 60 most looked-up of 2,033 medications checked with no known interaction — see the full Schizonepeta list.

See the full Schizonepeta interactions page
See every supplement checked against Acetaminophen, Codeine, 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
Schizonepeta monograph › Uses, safety, and every drug interaction in one place Acetaminophen, Codeine supplement interactions › Every supplement checked against Acetaminophen, Codeine, 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 Schizonepeta and Acetaminophen, Codeine Together: Common Questions

Can you take Schizonepeta with Acetaminophen, Codeine?
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 3 interactions listed for Schizonepeta and Acetaminophen, Codeine?
Acetaminophen, Codeine belongs to more than one drug category, and Schizonepeta 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 Schizonepeta and Acetaminophen, Codeine 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 Acetaminophen, Codeine and Schizonepeta?

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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.