Drug & supplement interaction

Schisandra + Quinidine

Quinidine brand names: Quinaglute Duratabs, Quinaglute, Duraquin, Cardioquin, Cin-Quin, and others.

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

Quinidine falls into 2 drug categories that Schisandra can interact with; the most serious is rated moderate. Schisandra can increase the levels and clinical effects of drugs metabolized by CYP3A4.

Read the full interaction report
SeverityModerate
LikelihoodProbable
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Schisandra and Quinidine

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Schisandra interacts with whole categories of medication. Quinidine falls into 2 of those categories, so it can interact with Schisandra in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

1 of 2

Why this applies to Quinidine

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

Schisandra can increase the levels and clinical effects of drugs metabolized by CYP3A4.
Most clinical and laboratory research shows that schisandra, administered either as a single dose or up to twice daily for 14 days, inhibits CYP3A4 and increases the concentration of CYP3A4 substrates such as cyclophosphamide, midazolam, tacrolimus, and talinolol. Although one in vitro and animal study shows that schisandra may induce CYP3A4 metabolism, this effect appears to be overpowered by schisandra's CYP3A4 inhibitory activity and has not been reported in humans.
Severity Moderate Likelihood Probable Evidence D

Interaction 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..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the gist for your situation. Your body relies on a liver enzyme called CYP3A4 to help break down quinidine. Schisandra appears to slow that enzyme down, so quinidine could clear more slowly and build up to higher levels than expected.

That matters because quinidine is a heart rhythm drug with a fairly narrow safety window. Higher levels can mean more side effects like nausea, diarrhea, ringing in the ears, dizziness, or in rare cases new rhythm problems, including a heart tracing change called QT prolongation. The good news is that this concern comes mostly from lab and animal research, not human studies, so it's a theoretical flag rather than a proven danger. Still, with a drug this sensitive, please check with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Iwata H, Tezuka Y, Kadota S, et al. Identification and characterization of potent CYP3A4 inhibitors in Schisandra fruit extract. Drug Metab Dispos 2004;32:1351-8. PubMed
  2. Mu Y, Zhang J, Zhang S, et al. Traditional Chinese medicines Wu Wei Zi (Schisandra chinensis Baill) and Gan Cao (Glycyrrhiza uralensis Fisch) activate pregnane X receptor and increase warfarin clearance in rats. J Pharmacol Exp Ther 2006;316:1369-77. PubMed
  3. Qin XL, Bi HC, Wang XD, et al. Mechanistic understanding of the different effects of Wuhzi Tablet (Schisandra sphenanthera extract) on the absorption and first-pass intestinal and hepatic metabolism of tacrolimus (FK506). Int J Pharm 2010;389:114-21.
  4. Makino, T., Mizuno, F., and Mizukami, H. Does a kampo medicine containing schisandra fruit affect pharmacokinetics of nifedipine like grapefruit juice? Biol.Pharm.Bull. 2006;29(10):2065-2069. PubMed
  5. Fan L, Mao XQ, Tao GY, Wang G, Jiang F, Chen Y, Li Q, Zhang W, Lei HP, Hu DL, Huang YF, Wang D, Zhou HH. Effect of Schisandra chinensis extract and Ginkgo biloba extract on the pharmacokinetics of talinolol in healthy volunteers. Xenobiotica. 2009 Mar;39(
  6. Jiang W, Wang X, Xu X, Kong L. Effect of Schisandra sphenanthera extract on the concentration of tacrolimus in the blood of liver transplant patients. Int J Clin Pharmacol Ther. 2010 Mar;48(3):224-9. PubMed
  7. Xin HW, Wu XC, Li Q, Yu AR, Xiong L. Effects of Schisandra sphenanthera extract on the pharmacokinetics of midazolam in healthy volunteers. Br J Clin Pharmacol. 2009 May;67(5):541-6.
  8. Li J, Chen S, Qin X, et at. Wuzhi Tablet (<i>Schisandra sphenanthera</i> Extract) is a Promising Tacrolimus-Sparing Agent for Renal Transplant Recipients Who are CYP3A5 Expressers: a Two-Phase Prospective Study. Drug Metab Dispos. 2017;45(11):1114-1119.
  9. Qin XL, Li JL, Wang SH, Chen X, Huang M, Bi HC. Co-administration of Wuzhi tablet (Schisandra sphenanthera extract) alters tacrolimus pharmacokinetics in a dose- and time-dependent manner in rats. J Ethnopharmacol. 2020;263:113233. PubMed
  10. Chen L, Ji N, Zhang M, Chen W. The influence of Wuzhi capsule on the pharmacokinetics of cyclophosphamide. Recent Pat Anticancer Drug Discov 2021. PubMed
  11. Cheng F, Li Q, Wang J, Zeng F, Zhang Y. Effects and safety evaluation of Wuzhi capsules combined with tacrolimus for the treatment of kidney transplantation recipients. J Clin Pharm Ther 2021;46(6):1636-49. PubMed
  12. Teng F, Wang W, Zhang W, et al. Effect of hepar-protecting Wuzhi capsule on pharmacokinetics and dose-effect character of tacrolimus in healthy volunteers. Biopharm Drug Dispos 2022.
  13. Kou K, Sun X, Li M, et al. Beneficial effects of Wuzhi capsule on tacrolimus blood concentrations in liver transplant patients with different donor-recipient CYP3A5 genotypes. J Clin Pharm Ther 2022;47(2):200-10. PubMed
  14. Peng Y, Jiang F, Zhou R, et al. Clinical evaluation of the efficacy and safety of co-administration of Wuzhi capsule and tacrolimus in adult Chinese patients with myasthenia gravis. Neuropsychiatr Dis Treat 2021;17:2281-9. PubMed
Moderate

P-GLYCOPROTEIN SUBSTRATES

2 of 2

Quinidine also falls under P-GLYCOPROTEIN SUBSTRATES.

Schisandra might increase the levels and clinical effects of P-glycoprotein substrates.
In vitro research shows that schisandra extracts and constituents such as schisandrin B inhibit P-glycoprotein mediated efflux in intestinal cells and in P-glycoprotein over-expressing cell lines. Additionally, a small clinical study shows that schisandra increases the peak concentration and overall exposure to talinolol, a P-glycoprotein probe substrate. Theoretically, schisandra might inhibit the efflux of other P-glycoprotein substrates.
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 for quinidine: it relies on a tiny pump in your gut and kidneys called P-glycoprotein to help move it along and keep your blood levels steady. Schisandra appears to slow that pump down, so less quinidine gets pushed out and more can build up in your system. Quinidine is an active drug (not a prodrug), so more of it means stronger effects.

Why that matters: quinidine has a narrow safety window, so even small jumps can tip you toward side effects like nausea, ringing in the ears, dizziness, or changes in your heart rhythm. Honestly though, this is based mostly on lab work and one small study, not on quinidine itself. Don't change anything on your own. Just give your pharmacist or doctor a heads-up before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Qin XL, Bi HC, Wang XD, et al. Mechanistic understanding of the different effects of Wuhzi Tablet (Schisandra sphenanthera extract) on the absorption and first-pass intestinal and hepatic metabolism of tacrolimus (FK506). Int J Pharm 2010;389:114-21.
  2. Fan L, Mao XQ, Tao GY, Wang G, Jiang F, Chen Y, Li Q, Zhang W, Lei HP, Hu DL, Huang YF, Wang D, Zhou HH. Effect of Schisandra chinensis extract and Ginkgo biloba extract on the pharmacokinetics of talinolol in healthy volunteers. Xenobiotica. 2009 Mar;39(
  3. Yoo HH, Lee M, Lee MW, Lim SY, Shin J, Kim DH. Effects of Schisandra lignans on P-glycoprotein-mediated drug efflux in human intestinal Caco-2. Planta Med. 2007;73(5):444-50.
  4. Qiangrong P, Wang T, Lu Q, Hu X. Schisandrin B--a novel inhibitor of P-glycoprotein. Biochem Biophys Res Commun. 2005;335(2):406-11. PubMed

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

Schisandra Also Interacts With Other Medications

Schisandra has 802 moderate known drug interactions in our database — the Quinidine one above is among them. If you take anything else, check it against the full list below.

Moderate 802 No known interaction 2,028 (incl. Quinidine)
Taking anything else?

Check Another of Your Medications Against Schisandra

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

From our Q&A

Questions About Schisandra or Quinidine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Schisandra or Quinidine, 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 Quinidine

This page covers Schisandra only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Quinidine page lists 207 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Beer (major) and Cesium (major).

By severity: 15 major · 157 moderate · 35 minor.

From our pharmacist’s overview on the Quinidine page

“Grapefruit belongs nowhere near quinidine. The juice blocks the main enzyme that clears this heart rhythm medicine, so quinidine levels can climb into dangerous territory, and it leads a list of 207 supplement and herbal ingredients I would treat with real seriousness, 15 of them rated major.”

Reviewed by 2 · Jul 18, 2026

Open the Quinidine interaction page

One more smart check

Taking Schisandra as Part of a Dietary Supplement Product? Check It for Interactions

We hold 2,577 real supplement products containing Schisandra, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Schisandra. Your product may carry other ingredients that interact with Quinidine too, on top of Schisandra — 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 Schisandra and Quinidine 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 Schisandra
Top 10%

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

29 days ago today
Medication Quinidine
Top 25%

#381 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 Schisandra

What is Schisandra?

Schisandra
  • Fatigue and low energy
  • Stress and adaptogen support
  • Liver health
  • Mental focus and performance
  • Menopause symptoms
  • Respiratory complaints

Schisandra is a traditional Chinese medicine berry used as an adaptogen for stress, fatigue, and liver support. Human evidence is limited and most claims are not well proven, but it appears reasonably well tolerated by most healthy adults when used short term. Pregnant and breastfeeding people should avoid it, and anyone with a health condition should check with a pharmacist or doctor first.

Read the full Schisandra monograph & all interactions
Medication

About Quinidine

What Is Quinidine Used For?

Brand names: Quinaglute Duratabs, Quinaglute, Duraquin, Cardioquin, Cin-Quin, Quinora, Lin-Qin, Quinova, Quinidex Extentabs

Quinidine is used to help restore a normal heart rhythm in people with atrial fibrillation or atrial flutter (irregular, rapid heart rhythms originating in the upper chambers). It is also used on an ongoing basis to reduce how often those episodes come back, in patients whose episodes are frequent and poorly tolerated — but only after other options have been tried first.

Quinidine sulfate oral tablets and quinidine gluconate extended-release oral tablets are both approved for these heart-rhythm uses. Quinidine sulfate tablets are additionally used as part of an approved treatment regimen for life-threatening Plasmodium falciparum malaria, in combination with quinidine gluconate injection (the central component of that regimen). Both formulations may also be used to suppress recurrent, documented life-threatening ventricular arrhythmias (dangerous rapid rhythms in the lower chambers of the heart), such as sustained ventricular tachycardia.

See full Quinidine drug information
Keep checking

Other Drugs & Schisandra

Browse every other medication we’ve checked against Schisandra — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
802Moderate
0Minor
2,027No known interaction
802 Moderate 2,027 No interaction
Moderate

802 interactions

Showing 60 of 802 moderate interactions — see all 802 on the Schisandra page.

No interaction 2,027 drugs checked — show the list

We also checked Schisandra against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,027 medications checked with no known interaction — see the full Schisandra list.

See the full Schisandra interactions page
See every supplement checked against Quinidine, 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
Schisandra monograph › Uses, safety, and every drug interaction in one place Quinidine supplement interactions › Every supplement checked against Quinidine, ranked by severity Quinidine 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 Schisandra and Quinidine Together: Common Questions

Can you take Schisandra with Quinidine?
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 2 interactions listed for Schisandra and Quinidine?
Quinidine belongs to more than one drug category, and Schisandra 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 Schisandra and Quinidine 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 Quinidine and Schisandra?

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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.