Drug & supplement interaction

Schizonepeta + Diltiazem

Diltiazem brand names: Cardizem, Cardizem SR, Diltiaz SR, Cardizem CD, Tiazac, and others.

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

Schizonepeta has a moderate interaction with Diltiazem. Animal research suggests that schizonepetin, a monoterpene constituent of schizonepeta, induces cytochrome P450 (CYP) 3A4.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Schizonepeta and Diltiazem

Here is the interaction we found between these two, with the evidence behind it.

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Diltiazem

Diltiazem falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Schizonepeta interacts with.

Animal research suggests that schizonepetin, a monoterpene constituent of schizonepeta, induces cytochrome P450 (CYP) 3A4. Theoretically, schizonepeta might decrease the effects of CYP3A4 substrates.
Some substrates of CYP3A4 include lovastatin (Mevacor), ketoconazole (Nizoral), itraconazole (Sporanox), fexofenadine (Allegra), triazolam (Halcion), and numerous 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 gist: your body uses a liver enzyme called CYP3A4 to break down diltiazem. Animal studies hint that a compound in Schizonepeta may speed that enzyme up. If that happens in people, your liver could clear diltiazem a little faster, which might leave less of it working in your system. The result could be weaker blood pressure or angina control, so you might notice numbers creeping up or more chest tightness.

I want to be honest about the strength here. This is based only on lab and animal work, not human studies, so it's theoretical and far from certain. Still, since diltiazem is doing an important job, it's worth a quick chat with your pharmacist or doctor before adding Schizonepeta rather than guessing on your own.

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 Diltiazem one above is one of them. If you take anything else, check it against the full list below.

Moderate 796 No known interaction 2,034 (incl. Diltiazem)
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.

From our Q&A

Questions About Schizonepeta or Diltiazem

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Schizonepeta or Diltiazem, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Diltiazem

This page covers Schizonepeta only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Diltiazem page lists 260 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Coleus (major) and Grapefruit (major).

By severity: 7 major · 214 moderate · 39 minor.

From our pharmacist’s overview on the Diltiazem page

“Someone on diltiazem (Cardizem, Tiazac) is usually managing blood pressure, angina, or a fast heart rhythm, so this list deserves genuine care. Seven of the 260 ingredients on file carry a major rating, and two of those are things people actually buy: grapefruit, which blocks the enzyme that clears diltiazem and can push its blood leve…”

Reviewed by 2 · Jul 18, 2026

Open the Diltiazem 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 Diltiazem 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 Diltiazem 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 half

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

29 days ago today
Medication Diltiazem
Top 25%

#295 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
Medication

About Diltiazem

What Is Diltiazem Used For?

Brand names: Cardizem, Cardizem SR, Diltiaz SR, Cardizem CD, Tiazac, Diltiaz XT, Diltiaz CD, Dilacor, Diltiaz, Cardizem LA, Dilacor XR, Cartia XT, Tiamate, Adizem-SR, Adizem-XL, Angitil SR, Angitil XL, Calcicard CR, Dilcardia SR, Dilzem SR, Dilzem XL, Slozem, Tildiem LA, Tildiem Retard, Viazem XL, Zemtard 120XL, Zemtard 180XL, Zemtard 240XL, Zemtard 300XL

Oral extended-release forms of diltiazem — including Matzim LA, Cardizem LA, Cartia, Cartia XT, Tiadylt ER, and various generic capsules and tablets — are used to treat high blood pressure (hypertension) and chronic stable angina (chest pain brought on by activity). Some capsule formulations, including Cartia, Cartia XT, and certain generics, are also approved for angina due to coronary artery spasm (sudden chest pain caused by a sudden tightening of a coronary artery).

Injectable forms of diltiazem are used in hospital settings to temporarily slow a dangerously fast heart rate in atrial fibrillation or atrial flutter (rapid, irregular heart rhythms), and to restore a normal heart rhythm in paroxysmal supraventricular tachycardia (PSVT) — sudden episodes of a very fast but regular heartbeat originating above the heart's lower chambers.

See full Diltiazem drug information
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 Diltiazem, 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 Diltiazem supplement interactions › Every supplement checked against Diltiazem, ranked by severity Diltiazem drug information › The full plain-English guide to this medication 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 Diltiazem Together: Common Questions

Can you take Schizonepeta with Diltiazem?
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.
How serious is the Schizonepeta and Diltiazem 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 Diltiazem and Schizonepeta?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.