Drug & supplement interaction

Fucus Vesiculosus + Amiodarone

Amiodarone brand names: Pacerone, Cordarone.

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

Amiodarone falls into 3 drug categories that Fucus Vesiculosus can interact with; the most serious is rated moderate. Theoretically, combining Fucus vesiculosus with amiodarone might cause excessively high iodine levels.

Read the full interaction report
SeverityModerate
LikelihoodProbable
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Fucus Vesiculosus and Amiodarone

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

Why Are There 3 Interactions?

Fucus Vesiculosus interacts with whole categories of medication. Amiodarone falls into 3 of those categories, so it can interact with Fucus Vesiculosus in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

AMIODARONE (Cordarone)

1 of 3
Theoretically, combining Fucus vesiculosus with amiodarone might cause excessively high iodine levels.
Fucus vesiculosus contains high concentrations of iodine. Amiodarone contains 37.3% iodine and can increase iodine levels. Concomitant use might increase the risk of having excessive iodine levels and adversely affecting thyroid function. Monitor thyroid function.
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 something a lot of people don't realize about amiodarone: by weight, it's more than a third iodine. Your body is already getting a big iodine load just from the medication itself. Now add bladderwrack, which is a seaweed packed with extra iodine, and you're potentially stacking iodine on top of iodine.

Too much iodine can throw your thyroid off in either direction, sometimes causing an underactive thyroid (tiredness, weight gain, feeling cold) and sometimes an overactive one (jitteriness, racing heart, weight loss). The last thing you want on a heart-rhythm drug is a thyroid problem. This concern is based on the chemistry rather than firm studies, but it's a sensible worry. Please check with your doctor or pharmacist before pairing these.

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

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 3

Why this applies to Amiodarone

Amiodarone falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Fucus Vesiculosus interacts with.

Theoretically, concomitant use of Fucus vesiculosus with CYP3A4 substrates might increase the risk for adverse effects.
In vitro research shows that fucoidan, a constituent of Fucus vesiculosus, inhibits CYP3A4. This interaction has not been reported in humans.
Severity Minor 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 amiodarone and bladderwrack (Fucus vesiculosus). Your liver uses an enzyme called CYP3A4 to help clear amiodarone. In lab dishes, a compound in bladderwrack called fucoidan slowed that enzyme down. If that happened in the body, amiodarone could build up a bit, which in theory might mean more side effects like a slow heartbeat, dizziness, tiredness, or nausea.

But honestly, this is only test-tube data and has never been reported in real people, so I wouldn't lose sleep over it. The bigger concern is the iodine in bladderwrack, since amiodarone itself is loaded with iodine and both affect the thyroid. Please run any seaweed supplement past your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Mathew L, Burney M, Gaikwad A, et al. Preclinical evaluation of safety of fucoidan extracts from Undaria pinnatifida and Fucus vesiculosus for use in cancer treatment. Integr Cancer Ther 2017;16(4):572-84.
Minor

CYTOCHROME P450 2C8 (CYP2C8) SUBSTRATES

3 of 3

Amiodarone also falls under CYTOCHROME P450 2C8 (CYP2C8) SUBSTRATES.

Theoretically, concomitant use of Fucus vesiculosus with CYP2C8 substrates might increase the risk for adverse effects.
In vitro research shows that fucoidan, a constituent of Fucus vesiculosus, inhibits CYP2C8. This interaction has not been reported in humans.
Severity Minor 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 short version on combining bladderwrack (Fucus vesiculosus) with amiodarone. Lab studies suggest one of its components, fucoidan, may slow down a liver enzyme called CYP2C8, which is one of the pathways that helps clear amiodarone. In theory, that could let amiodarone build up a bit, which might mean more of its known side effects, like a slow heartbeat, low blood pressure, dizziness, or fatigue.

That said, this is only a theoretical, test-tube finding and hasn't been seen in actual patients, so I wouldn't lose sleep over it. The bigger concern is the seaweed's high iodine content, which can throw off your thyroid, something amiodarone already affects. Please run this by your pharmacist or doctor before using it.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Mathew L, Burney M, Gaikwad A, et al. Preclinical evaluation of safety of fucoidan extracts from Undaria pinnatifida and Fucus vesiculosus for use in cancer treatment. Integr Cancer Ther 2017;16(4):572-84.

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

Fucus Vesiculosus Also Interacts With Other Medications

Fucus Vesiculosus has 22 moderate, 868 minor known drug interactions in our database — the Amiodarone one above is among them. If you take anything else, check it against the full list below.

Moderate 22 Minor 868 No known interaction 1,940 (incl. Amiodarone)
Taking anything else?

Check Another of Your Medications Against Fucus Vesiculosus

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

From our Q&A

Questions About Fucus Vesiculosus or Amiodarone

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

This page covers Fucus Vesiculosus only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Amiodarone page lists 210 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: 11 major · 163 moderate · 36 minor.

From our pharmacist’s overview on the Amiodarone page

“Amiodarone (Pacerone, Cordarone) treats dangerous heart rhythms, and this is one supplement list I would genuinely be careful with. Of the 210 ingredients on file, 11 carry a major rating, and the everyday one is grapefruit, which blocks the liver enzyme that clears amiodarone and can push the drug's level higher than intended.”

Reviewed by 2 · Jul 18, 2026

Open the Amiodarone interaction page

How much people look this up

Where Fucus Vesiculosus and Amiodarone 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 Fucus Vesiculosus
Steady interest

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

29 days ago today
Medication Amiodarone
Top 25%

#366 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 Fucus Vesiculosus

What is Fucus Vesiculosus?

Fucus Vesiculosus
  • Thyroid support
  • Iodine source
  • Weight management
  • Joint and skin care (topical)
  • Constipation and digestive support

Fucus vesiculosus (bladderwrack) is a brown seaweed rich in iodine that has been used traditionally for thyroid concerns, weight, and skin. There is little solid human evidence to support most of these uses, and its high and variable iodine content can actually harm the thyroid. Talk to a pharmacist or doctor before using it, especially if you have a thyroid condition.

Read the full Fucus Vesiculosus monograph & all interactions
Medication

About Amiodarone

What Is Amiodarone Used For?

Brand names: Pacerone, Cordarone

Amiodarone is prescribed for adults with serious, life-threatening heart-rhythm problems that haven't responded to other medications. Specifically, it's used for two dangerous arrhythmias (abnormal heartbeats): recurrent ventricular fibrillation (a chaotic, potentially fatal heart rhythm) and recurrent ventricular tachycardia (a dangerously fast heart rhythm that causes unstable blood pressure).

Because amiodarone comes with significant risks, doctors reserve it for situations where other options haven't worked or can't be tolerated. It is not a first-choice medication — it's a last-resort tool for serious, life-threatening conditions.

See full Amiodarone drug information
Keep checking

Other Drugs & Fucus Vesiculosus

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

0Major
22Moderate
868Minor
1,939No known interaction
22 Moderate 868 Minor 1,939 No interaction
Moderate

22 interactions

Minor

868 interactions

Showing 60 of 868 minor interactions — see all 868 on the Fucus Vesiculosus page.

No interaction 1,939 drugs checked — show the list

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

Showing the 60 most looked-up of 1,939 medications checked with no known interaction — see the full Fucus Vesiculosus list.

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

Can you take Fucus Vesiculosus with Amiodarone?
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 Fucus Vesiculosus and Amiodarone?
Amiodarone belongs to more than one drug category, and Fucus Vesiculosus 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 Fucus Vesiculosus and Amiodarone 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 Amiodarone and Fucus Vesiculosus?

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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.