Drug & supplement interaction

Ascophyllum Nodosum + Quinidine

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

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Ascophyllum Nodosum and Quinidine in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Ascophyllum Nodosum and Quinidine

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Quinidine and Ascophyllum Nodosum in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Ascophyllum Nodosum safety at a glance

Ascophyllum Nodosu... overall Use caution Generally used in foods, but its iodine content and possible heavy metal contamination warrant caution.
Pregnancy Avoid Avoid due to high iodine levels and possible contaminants that may affect the baby.
Breastfeeding Avoid Avoid because iodine and contaminants can pass into breast milk.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Quinidine and Ascophyllum Nodosum? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Quinidine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Quinidine is filed under 9 classifications — including cytochrome p450 2d6 (cyp2d6) inhibitors, qt interval-prolonging drugs, p-glycoprotein substrates. Ascophyllum Nodosum has documented interactions with 3 drug classes — the most serious being amiodarone (cordarone) (moderate), antithyroid drugs (moderate) and thyroid hormone (moderate) — and none of Quinidine’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Ascophyllum Nodosum Does Interact With Other Medications

Ascophyllum Nodosum has 22 moderate known drug interactions in our database — Quinidine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 22 No known interaction 2,808 (incl. Quinidine)
Taking anything else?

Check Another of Your Medications Against Ascophyllum Nodosum

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

What to actually watch for

What Quinidine’s Own FDA Label Lists

This is not an interaction — none of it involves Ascophyllum Nodosum. These are the most notable effects listed in the ADVERSE REACTIONS section of Quinidine’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you take both. 10 of them are worth acting on rather than waiting out — marked below.

  • Loss of vision Worth acting on
  • Hearing loss Worth acting on
  • Unsteadiness Worth acting on
  • Fainting Worth acting on
  • Wheezing Worth acting on
  • An irregular heartbeat Worth acting on
  • Confusion Worth acting on
  • Seizures Worth acting on
  • Low mood Worth acting on
  • A low platelet count Worth acting on

Showing the 10 most notable of 33 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Quinidine. Read the label on DailyMed › Ascophyllum Nodosum’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Ascophyllum Nodosum side to compare — that is a limit of the record, not a statement that Ascophyllum Nodosum has no side effects.

From our Q&A

Questions About Ascophyllum Nodosum 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 Ascophyllum Nodosum 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 Ascophyllum Nodosum 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 Ascophyllum Nodosum as Part of a Dietary Supplement Product? Check It for Interactions

We hold 360 real supplement products containing Ascophyllum Nodosum, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Ascophyllum Nodosum. Even though Ascophyllum Nodosum itself has no known interaction with Quinidine, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Ascophyllum Nodosum 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 Ascophyllum Nodosum
Top half

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

29 days ago today
Medication Quinidine
Top 25%

#685 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Ascophyllum Nodosum reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Ascophyllum Nodosum and Quinidine records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Ascophyllum Nodosum

What is Ascophyllum Nodosum?

Ascophyllum Nodosum
  • Weight management
  • Blood sugar support
  • Thyroid support (iodine source)
  • Digestive health
  • Source of vitamins and minerals
  • Joint comfort

Ascophyllum nodosum (often sold as bladderwrack or brown seaweed) is a nutrient-rich algae that people use for weight, blood sugar, and thyroid support, but solid human evidence is limited for most of these uses. Because it naturally contains iodine and can absorb heavy metals like arsenic, it should be used cautiously, and pregnant or breastfeeding people should avoid it unless a doctor approves.

Ascophyllum nodosum · Fucaceae · Whole seaweed (thallus/fronds) · Capsules, tablets, powder, extracts, teas, and topical products

An interaction check asks whether these two react with each other — it does not ask whether Ascophyllum Nodosum is a good idea for someone in your situation. Here is what our Ascophyllum Nodosum record says about it on its own.

Ascophyllum Nodosum: dosing

There is no well-established standard dose of Ascophyllum nodosum. Products vary widely in strength and iodine content, which makes consistent dosing difficult.If you choose to use it, follow the directions on the product label and do not exceed the recommended amount.

From our Ascophyllum Nodosum monograph — the full record covers uses, side effects and every documented interaction.

Read the full Ascophyllum Nodosum 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 & Ascophyllum Nodosum

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

0Major
22Moderate
0Minor
2,807No known interaction
22 Moderate 2,807 No interaction
Moderate

22 interactions

No interaction 2,807 drugs checked — show the list

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

Showing the 60 most looked-up of 2,807 medications checked with no known interaction — see the full Ascophyllum Nodosum list.

See the full Ascophyllum Nodosum interactions page
See every supplement checked against Quinidine, ranked by severity
Evidence & sources

Ascophyllum Nodosum References

The 5 references that drive our Ascophyllum Nodosum monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2002.
  2. Sterling JB, Heymann WR. Potassium iodide in dermatology: a 19th century drug for the 21st century-uses, pharmacology, adverse effects, and contraindications. J Am Acad Dermatol 2000;43:691-7. PubMed
  3. Combet E, Ma ZF, Cousins F, et al. Low-level seaweed supplementation improves iodine status in iodine-insufficient women. Br J Nutr 2014;112:753-61. PubMed
  4. Simmons-Boyce JL, Purcell SL, Nelson CM, MacKinnon SL. Dietary Ascophyllum nodosum increases urinary excretion of tricarboxylic acid cycle intermediates in male Sprague-dawley rats. J Nutr 2009;139:1487-94. PubMed
  5. Sorge US, Henriksen M, Bastan A, et al. Short communication: Iodine concentrations in serum, milk, and tears after feeding Ascophyllum nodosum to dairy cows-A pilot study. J Dairy Sci 2016;99:8472-6. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Ascophyllum Nodosum and Quinidine Together: Common Questions

Is it safe to take Ascophyllum Nodosum with Quinidine?
We do not list a known interaction between Ascophyllum Nodosum and Quinidine. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
How was the Ascophyllum Nodosum and Quinidine combination checked?
Interactions in our licensed database are recorded against drug classes. Quinidine is filed under 9 classifications, and Ascophyllum Nodosum has documented interactions with 3 drug classes — none of Quinidine's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Ascophyllum Nodosum interact with any other medications?
Yes. Ascophyllum Nodosum has 22 documented drug interactions in our database — Quinidine is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Quinidine interact with any supplements?
Yes. Quinidine has documented interactions with 207 supplements in our database — Ascophyllum Nodosum is not one of them. The Quinidine interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Ascophyllum Nodosum monograph Uses, safety profile, and every drug interaction in one place Quinidine drug information The full plain-English guide to this medication Quinidine supplement interactions Every supplement checked against Quinidine, 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 References The 5 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Quinidine and Ascophyllum Nodosum?

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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.