Drug & supplement interaction

Swamp Milkweed + Digoxin

Digoxin brand names: Lanoxicaps, Lanoxin, Digitek.

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

Swamp Milkweed has a major interaction with Digoxin. Theoretically, swamp milkweed might increase the risk of adverse effects and toxicity when taken with digoxin.

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

Swamp Milkweed and Digoxin

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

Major

DIGOXIN (Lanoxin)

Theoretically, swamp milkweed might increase the risk of adverse effects and toxicity when taken with digoxin.
Swamp milkweed contains cardioactive steroids known as cardenolides that may have digitalis-like activity.
Severity Major Likelihood Likely Evidence D

Well-controlled human studies have demonstrated the likely existence of this interaction.

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

Here's the thing about Swamp Milkweed and digoxin: this plant contains compounds called cardenolides that act a lot like digoxin itself. So instead of one heart drug in your system, you'd essentially be stacking two similar heart-acting substances on top of each other. That can push you toward digoxin toxicity.

Digoxin already has a very narrow safety window, meaning the gap between a helpful dose and a harmful one is small. Adding milkweed's digitalis-like activity could tip you over. Warning signs of too much digoxin include nausea, loss of appetite, blurry or yellow-tinted vision, confusion, and a slow or irregular heartbeat. To be fair, this concern is based on the plant's chemistry rather than human studies, but Swamp Milkweed is genuinely toxic and not a supplement to take. Please talk with your pharmacist or doctor before combining anything with digoxin.

Contact Dr. Brian directly if you have additional questions on this interaction
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 2 major, 153 moderate known drug interactions in our database — the Digoxin one above is one of them. If you take anything else, check it against the full list below.

Major 2 Moderate 153 No known interaction 2,675 (incl. Digoxin)
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.

From our Q&A

Questions About Swamp Milkweed or Digoxin

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

This page covers Swamp Milkweed only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Digoxin page lists 113 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Aloe (major), Blue Flag (major), Danshen (major) and European Buckthorn (major).

By severity: 18 major · 79 moderate · 16 minor.

From our pharmacist’s overview on the Digoxin page

“Digoxin is a heart medicine with a narrow therapeutic index, meaning the gap between a helpful blood level and a harmful one is small, and few drugs give me more pause when supplements enter the picture. The most serious entries here are herbs that themselves contain digoxin-like cardiac glycosides, foxglove and lily-of-the-valley amon…”

Reviewed by 2 · Jul 18, 2026

Open the Digoxin interaction page

How much people look this up

Where Swamp Milkweed and Digoxin 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

#1,217 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Digoxin
Top 25%

#542 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 Digoxin

What Is Digoxin Used For?

Brand names: Lanoxicaps, Lanoxin, Digitek

Digoxin tablets, oral solution, and injections (including Lanoxin brand) are all approved to treat mild to moderate heart failure in adults — improving symptoms like exercise tolerance and reducing hospitalizations, though it does not extend life. It is also approved to control the resting ventricular rate (how fast the lower chambers beat) in adults with chronic atrial fibrillation. The oral solution specifically notes it should not be used for multifocal atrial tachycardia.

In children with heart failure, digoxin is used to strengthen the heart's contractions (increase myocardial contractility). Digoxin is best used alongside a diuretic (water pill) and an ACE inhibitor when possible.

See full Digoxin 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.

2Major
153Moderate
0Minor
2,674No known interaction
2 Major 153 Moderate 2,674 No interaction
Major

2 interactions

Moderate

153 interactions

Showing 60 of 153 moderate interactions — see all 153 on the Swamp Milkweed page.

No interaction 2,674 drugs checked — show the list

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

Showing the 60 most looked-up of 2,674 medications checked with no known interaction — see the full Swamp Milkweed list.

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

Can you take Swamp Milkweed with Digoxin?
This is rated a major interaction, so the combination is best avoided unless your doctor or pharmacist has specifically told you otherwise. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Swamp Milkweed and Digoxin interaction?
We rate it Major. This is a clinically significant combination that is generally best avoided, or used only under the direct supervision of your physician or pharmacist.

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

Still Have a Question About Digoxin and Swamp Milkweed?

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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.