Drug & supplement interaction

Swamp Milkweed + Azithromycin

Azithromycin brand names: Zithromax, Zmax, Azasite.

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

Swamp Milkweed has a moderate interaction with Azithromycin. Theoretically, macrolide antibiotics might increase the risk of toxicity from cardioactive steroids in 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 Azithromycin

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

Moderate

MACROLIDE ANTIBIOTICS

Why this applies to Azithromycin

Azithromycin falls under MACROLIDE ANTIBIOTICS — the group Swamp Milkweed interacts with.

Theoretically, macrolide antibiotics might increase the risk of toxicity from cardioactive steroids in swamp milkweed.
Swamp milkweed contains cardioactive steroids known as cardenolides that may have digitalis-like activity. Macrolide antibiotics appear to increase the gastrointestinal absorption of oral digoxin. Theoretically, concomitant use of macrolide antibiotics might increase the absorption of the cardenolides found in swamp milkweed and increase the risk of adverse effects.
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 gist for azithromycin (Zithromax) and swamp milkweed. Swamp milkweed contains heart-active compounds called cardenolides, which behave a lot like digoxin, a heart medication. Antibiotics in azithromycin's family can boost how much of these gut-absorbed compounds your body takes in. So the worry is that pairing them could raise the amount of these heart-affecting compounds in your system, which might lead to nausea, an irregular or slow heartbeat, dizziness, or palpitations.

I want to be honest about the strength of this: it's theoretical, based on how these substances behave rather than real cases in people. Still, swamp milkweed is genuinely toxic and isn't a proven supplement to begin with. I'd skip using it, and please check with your pharmacist or doctor before combining it with any medicine.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
  2. 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 Azithromycin one above is one of them. If you take anything else, check it against the full list below.

Major 3 Moderate 152 No known interaction 2,675 (incl. Azithromycin)
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 Azithromycin

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 Azithromycin, 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 Azithromycin

This page covers Swamp Milkweed only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Azithromycin page lists 92 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), Cesium (major) and Ephedra (major).

By severity: 8 major · 71 moderate · 13 minor.

From our pharmacist’s overview on the Azithromycin page

“A five-day Z-Pak for a sinus or chest infection seems too brief to fuss over, but azithromycin (Zithromax, Zmax) deserves genuine caution around supplements, and the eight major-rated entries on this list are the ones to understand first. Most of those involve the heart.”

Reviewed by 2 · Jul 18, 2026

Open the Azithromycin interaction page

How much people look this up

Where Swamp Milkweed and Azithromycin 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

#1,209 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Azithromycin
Top 5%

#60 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 Azithromycin

What Is Azithromycin Used For?

Brand names: Zithromax, Zmax, Azasite

  • Azithromycin is used to treat certain bacterial infections, such as bronchitis; pneumonia; sexually transmitted diseases (STD); and infections of the ears, lungs, sinuses, skin, throat, and reproductive organs. Azithromycin also is used to treat or prevent disseminated Mycobacterium avium complex (MAC) infection [a type of lung infection that often affects people with human immunodeficiency virus (HIV)]. Azithromycin is in a class of medications called macrolide antibiotics. It works by stopping the growth of bacteria.

  • Antibiotics such as azithromycin will not work for colds, flu, or other viral infections. Using antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment.

See full Azithromycin 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
3 Major 152 Moderate 2,674 No 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

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 Azithromycin, 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 Azithromycin supplement interactions › Every supplement checked against Azithromycin, ranked by severity Azithromycin 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 Azithromycin Together: Common Questions

Can you take Swamp Milkweed with Azithromycin?
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 Azithromycin 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 Azithromycin 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.