Drug & supplement interaction

Polypodium Leucotomos + Quinidine

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

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

Polypodium Leucotomos has a minor interaction with Quinidine. Theoretically, Polypodium leucotomos might increase levels of drugs metabolized by CYP3A4.

Read the full interaction report
SeverityMinor
LikelihoodUnlikely
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Polypodium Leucotomos and Quinidine

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

Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Quinidine

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

Theoretically, Polypodium leucotomos might increase levels of drugs metabolized by CYP3A4.
In vitro and animal research suggests that Polypodium leucotomos can decrease the metabolism of midazolam by a mechanism possibly related to the inhibition of CYP3A4. However, a small study in humans suggests that taking Polypodium leucotomos with midazolam does not affect the metabolism of midazolam.
Severity Minor Likelihood Unlikely Evidence B

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

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

Here's the short version: your body partly clears quinidine using a liver enzyme called CYP3A4. In test tube and animal studies, Polypodium leucotomos seemed to slow that enzyme down a little. If that happened in people, quinidine could build up slightly and you might notice more of its effects or side effects, like ringing in the ears, dizziness, nausea, or changes in your heart rhythm. Quinidine is a drug where small shifts can matter, so that's worth knowing.

That said, the human evidence is reassuring. A small study using a similar test medication showed no real change, so this concern stays mostly theoretical. Still, since quinidine is for your heartbeat, please check with your pharmacist or doctor before adding this fern extract.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Shinya K, Nishimura Y, Ryu K, et al. Short-term administration of Polypodium leucotomos extract does not inhibit CYP3A4-mediated metabolism of midazolam in healthy subjects: an open-label, two-period, fixed-sequence study. Int J Dermatol 2022.

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

Polypodium Leucotomos Also Interacts With Other Medications

Polypodium Leucotomos has 642 minor known drug interactions in our database — the Quinidine one above is one of them. If you take anything else, check it against the full list below.

Minor 642 No known interaction 2,188 (incl. Quinidine)
Taking anything else?

Check Another of Your Medications Against Polypodium Leucotomos

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

From our Q&A

Questions About Polypodium Leucotomos 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 Polypodium Leucotomos 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 Polypodium Leucotomos 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 Polypodium Leucotomos as Part of a Dietary Supplement Product? Check It for Interactions

We hold 26 real supplement products containing Polypodium Leucotomos, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Polypodium Leucotomos. Your product may carry other ingredients that interact with Quinidine too, on top of Polypodium Leucotomos — 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 Polypodium Leucotomos 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 Polypodium Leucotomos
Steady interest

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

29 days ago today
Medication Quinidine
Top 25%

#370 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 Polypodium Leucotomos

What is Polypodium Leucotomos?

  • Sun sensitivity and sunburn protection
  • Skin conditions like vitiligo and melasma
  • Polymorphic light eruption
  • Skin aging and photoaging
  • Atopic dermatitis support

Polypodium leucotomos is a fern extract taken by mouth, mostly studied as an add-on to (not a replacement for) sunscreen and for certain light-triggered skin conditions. Some early research is promising for reducing sun sensitivity, but the evidence is still limited and it should not replace standard sun protection. Talk with your pharmacist or doctor before starting it.

Read the full Polypodium Leucotomos 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 & Polypodium Leucotomos

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

0Major
0Moderate
642Minor
2,187No known interaction
642 Minor 2,187 No interaction
Minor

642 interactions

Showing 60 of 642 minor interactions — see all 642 on the Polypodium Leucotomos page.

No interaction 2,187 drugs checked — show the list

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

Showing the 60 most looked-up of 2,187 medications checked with no known interaction — see the full Polypodium Leucotomos list.

See the full Polypodium Leucotomos 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
Polypodium Leucotomos 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 Polypodium Leucotomos and Quinidine Together: Common Questions

Can you take Polypodium Leucotomos with Quinidine?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Polypodium Leucotomos and Quinidine interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Quinidine and Polypodium Leucotomos?

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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.