Drug & supplement interaction

Swamp Milkweed + Amiloride, Hydrochlorothiazide

Amiloride, Hydrochlorothiazide brand names: Moduretic, Amilzide, Moduret 25, Amil-Co.

Moderate Interaction
The bottom line Moderate

Swamp Milkweed has a moderate interaction with Amiloride, Hydrochlorothiazide. Theoretically, potassium depleting diuretics might increase the risk of toxicity with swamp milkweed.

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

Swamp Milkweed and Amiloride, Hydrochlorothiazide

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

Moderate

DIURETIC DRUGS

Why this applies to Amiloride, Hydrochlorothiazide

Amiloride, Hydrochlorothiazide falls under DIURETIC DRUGS — the group Swamp Milkweed interacts with.

Theoretically, potassium depleting diuretics might increase the risk of toxicity with swamp milkweed.
Swamp milkweed contains cardioactive steroids known as cardenolides that may have digitalis-like activity. Potassium depletion can increase the risk of cardenolide toxicity.
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 thing about Swamp Milkweed: it contains heart-acting compounds called cardenolides that behave a bit like the old heart drug digitalis. Your blood pressure pill is a two-part combo. The hydrochlorothiazide side can lower your body's potassium, while the amiloride side is actually 'potassium-sparing' and helps hold potassium in. So the net effect on your potassium depends on the person.

Why this matters: low potassium makes the heart more sensitive to those milkweed cardenolides, which can raise the risk of toxic effects like an irregular or unusually slow heartbeat, nausea, or confusion. To be clear, this is a theoretical concern based on how these compounds behave, not strong human studies. Honestly, Swamp Milkweed isn't a proven supplement and can be toxic, so please don't take it without checking with your doctor or pharmacist first.

References
  1. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

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

Swamp Milkweed Also Interacts With Other Medications

Swamp Milkweed has 3 major, 152 moderate known drug interactions in our database — the Amiloride, Hydrochlorothiazide one above is one of them. If you take anything else, check it against the full list below.

Taking anything else?

Check Another of Your Medications Against Swamp Milkweed

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

Everything else you take

See Every Supplement That Interacts With Amiloride, Hydrochlorothiazide

This page covers Swamp Milkweed only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Amiloride, Hydrochlorothiazide page lists 236 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), Asarabacca (major) and Dolomite (major).

By severity: 10 major · 199 moderate · 27 minor.

From our pharmacist’s overview on the Amiloride, Hydrochlorothiazide page

“The typical Moduretic (amiloride with hydrochlorothiazide) patient is managing blood pressure long term, and the supplements that crowd reaches for (herbal blood pressure aids, potassium, calcium) are exactly what fills this list. It deserves a careful read, not a skim.”

Reviewed by 2 · Jul 18, 2026

Open the Amiloride, Hydrochlorothiazide interaction page

How much people look this up

Where Swamp Milkweed and Amiloride, Hydrochlorothiazide 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 Swamp Milkweed
Steady interest

#1,238 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Amiloride, Hydrochlorothiazide
Top 10%

#242 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 Swamp Milkweed

What is Swamp Milkweed?

  • Traditional digestive remedy
  • Diuretic (increasing urine)
  • Cough and respiratory complaints
  • Worm or parasite remedy (folk use)
  • Pollinator/garden plant rather than medicine

Swamp Milkweed is a native North American wetland plant best known today as a butterfly and pollinator garden plant, not a proven medicine. It contains toxic milky sap with cardiac glycoside-like compounds, and there is very little reliable human research to support any health use. Because of its potential toxicity, it should not be used as a supplement without professional guidance.

Read the full Swamp Milkweed monograph & all interactions
Medication

About Amiloride and Hydrochlorothiazide

What Is Amiloride and Hydrochlorothiazide Used For?

Brand names: Moduretic, Amilzide, Moduret 25, Amil-Co

Amiloride hydrochloride and hydrochlorothiazide tablets are used for patients with high blood pressure (hypertension) or congestive heart failure who tend to develop low potassium (hypokalemia) when taking a thiazide or other diuretic alone — or for whom keeping potassium levels in a normal range is especially important, such as people taking digoxin or those with significant heart rhythm problems.

The tablets may be used on their own or alongside other blood pressure medicines, such as methyldopa or beta blockers. This combination product is not intended as the first-choice treatment for swelling (edema) or high blood pressure unless low potassium is a specific concern.

See full Amiloride and Hydrochlorothiazide drug information
Keep checking

Other Drugs & Swamp Milkweed

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

3Major
152Moderate
0Minor
2,674No known interaction
Major

3 interactions

Moderate

152 interactions

Showing 60 of 152 moderate interactions — see all 152 on the Swamp Milkweed page.

No interaction 2,674 drugs checked — show the list
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

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Pharmacist Counseling Corner

Taking Swamp Milkweed and Amiloride, Hydrochlorothiazide Together: Common Questions

Can you take Swamp Milkweed with Amiloride, Hydrochlorothiazide?
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 Swamp Milkweed and Amiloride, Hydrochlorothiazide 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

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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.